T&DI Congress 2014: Planes, Trains, and Automobiles

Open-graded aggregate base courses have been increasingly used in Portland cement concrete (PCC) pavements as one of the effective strategies for improving subsurface drainage efficiency and thus pavement longevity. In addition to maintaining adequate permeability, these layers are also required to remain stable during pavement construction, performance period and future rehabilitation activities. In an effort to study subsurface drainage and stability of a new open-graded aggregate base material (OGAB Special) under construction, PCC pavement test sections (Cells 306 and 406) were constructed by the Minnesota Department of Transportation (MnDOT) on the 3.5-mile mainline interstate roadway segment at the MnROAD test facility in 2011. Both test cells consist of 6-in. thick PCC slab, 6-in. thick OGAB Special layer and 7-in. Class 5 (MnDOT traditional dense-graded) unbound aggregate underlain by clay subgrade. This paper presents the findings from analyzing field instrumentation data and Falling Weight Deflectometer (FWD) test results to assess the effectiveness of the OGAB Special layer in controlling subsurface moisture regime and providing structural stability. For comparison, field test data were also collected and analyzed from MnROAD Cells 38, 53, and 54 that are located in the low-volume roadway segment and consist of PCC slabs of similar thickness and traditional dense-graded base layers (Class 5 or 6) underlain by clay subgrade. It was concluded from analysis results that the OGAB Special layer cannot only reduce the subsurface moisture content significantly but also provide comparable structural stability, as compared to traditional dense-graded (Class 5/6) base layers.

The Superpave mix design process involves finding optimum asphalt content for a specified gradation that would result in desired percent air voids, voids in mineral aggregates (VMA), voids filled with asphalt (VFA), dust proportion, and percent G_mm at N_ini and N_max. The mix design criteria include a minimum VMA to ensure durability. The other related volumetric parameters are VFA and dust proportion. Bulk specific gravity (G_sb) of the blended aggregates is needed to calculate VMA and subsequently VFA, and dust proportion. With Reclaimed Asphalt Pavement (RAP) becoming more popular and with higher and higher percentage of it being used in Superpave mixtures, precise RAP bulk specific gravity ( G^RAP_sb) is essential for designing durable Suparepave mixtures. The FHWA-recommended method for calculating RAP aggregate G_sb is based on a number of assumptions including asphalt absorption of the aggregates. In this study, Superpave mixtures with 20, 30, and 40 percent RAP and fractionated RAP where tested to find out how these assumptions can influence volumetric properties of the Superpave mixtures with high RAP content. In addition, G_sb tests were conducted on the aggregates obtained from the solvent extraction and ignition burn-off methods. The calculated volumetric properties were compared with the results from that obtained using G^RAP_sb from the FHWA- recommended method. The results show that volumetric properties obtained from two test methods can vary significantly.

The development of model to estimate the Graded Aggregate Base (GAB) resilient modulus is described in this paper. Eleven (11) different sources of GAB available locally in Georgia were subjected to the resilient modulus test in accordance with AASHTO T 307-99 with two replicates. The stress state and physical properties of resilient behavior of GAB were then successfully correlated using an Artificial Neural Network (ANN) model. The study indicates that the stress state and physical properties of GAB affect the resilient behavior of GAB, which in turn has a substantial effect on the pavement response and design. In this study, the ANN was trained using Bayesian regulation back-propagation algorithm to overcome problems associated with over-fitting. The model results indicated that the ANN reasonably estimated the GAB resilient modulus based on the stress state and physical properties of the aggregate.

Fatigue cracking is a primary distress in asphalt concrete (AC) due to repetitive stresses and strains caused by both traffic loading and environmental factors. The fatigue resistance of AC is investigated by a number of fatigue tests. The main objective of this study is to compare the fracture properties of AC under Beam Fatigue Test (BFT) and the Semi-circular Bending (SCB) test using non-contact camera and crosshead movement. A comprehensive comparison of fracture properties of six AC mixtures from the SCB non-contact camera method, SCB Cross Head Movement (CHM) method and Beam Fatigue test (BFT) was conducted. The critical strain energy (J_c) and K_1c values for AC mixtures are determined. BFT was performed on the same mixtures and initial stiffness, N_f and PV are determined. Comparison between the tests parameters was performed, and the Jc and K1c of SCB non-contact camera and CHM methods indicated lower fracture properties for PG64-10RAP (LIME), AN-HMA and WMA-ADVERA and higher fracture properties for 710P4-AR, AN-WMA and PG64-28PM mixtures. Similar results were achieved by BFT Nf and PV parameters. Data analysis showed that there is a linear correlation between Jc and K1c from the both SCB test methods, a good correlation between Nf and PV with Jc, and poor correlation between initial stiffness with Jc, Nf and PV. This has indicated that the initial stiffness is not a good representative for fracture properties of AC while Jc, Nf and PV are better indicators. The results of this study indicate that the SCB test has a great potential as a QA/QC test of fracture properties of asphalt mixtures.

This study focused on reducing duration of the Hamburg wheel-tracking device (HWTD) test. Four fine-graded Superpave mixtures with 12.5-mm Nominal Maximum Aggregate Size (NMAS) were selected for this study. The average number of wheel passes to a 20-mm rut depth in the HWTD tests was used to build accelerated life models with a Weibull distribution. Good consistency between the accelerated life (statistical) model-predicted and observed test results was obtained for the standard load level (705 N) and 60°C test temperature. The HWTD test duration can be reduced to about two hours when higher test temperature is used.

The Asphalt Pavement Analyzer (APA) is a laboratory accelerated pavement test device that has been used by many researchers and agencies as a tool to assess rutting potential of asphalt mixtures. Typically, the test is performed on cylindrical or beam specimens using a vertical load of 445 N, a hose inflation pressure of 690 kPa, and a test temperature equal to the high binder performance grade (PG) temperature. A simulated wheel load is repetitively applied to test specimens, typically for 8,000 cycles, and the rut depth is measured as a function of load cycles. This study evaluated the sensitivity of the APA to specimen preparation procedures (e.g., mixing, compaction, and volumetrics) and test parameters (e.g., temperature, wheel load, and hose pressure). Results from the study indicate several parameters can have an important impact on APA performance. These influences become important considerations when using the APA as a design or performance assessment tool.

In a developing country like India, periodic evaluation of low volume urban roads is required to prioritize the order of maintenance and rehabilitation of road network. This paper presents a typical case study of an urban road network of Tumkur city, Karnataka, India. Six roads stretches of the selected road network were investigated for traffic volume, functional and structural condition in terms of CBR value of the subgrade soil, rebound deflection from Benkelman Beam Deflection(BBD) survey, International Roughness Index(IRI) using Machine for Evaluating Roughness using Low-cost Instrumentation(MERLIN) and condition rating based on extent of cracking, patching, rutting and potholes. The structural condition is evaluated using KENLAYER software to obtain the critical strains. Two of the existing measures of pavement condition are used to evaluate the pavement condition and to decide the order of maintenance priority for the selected road network. It is found that the two methods viz Pavement Condition Index (PCI) and Maintenance Priority Index (MPI) do not yield a satisfactory ranking of the maintenance requirement. A more comprehensive prioritization index called Modified Maintenance Priority Index (MMPI) is proposed and is found to give realistic ranking of the maintenance priority requirement of the selected road network.

A recently developed test method is presented that uses a modified version of the ASTM C 231 pressure meter to measure the air void volume and distribution of fresh concrete. The device is called the Super Air Meter, or SAM, and is portable, easy to use, and the test can be completed in 10 minutes. The result is a vast improvement over the 14 days that is typically required for an ASTM C 457 hardened air void analysis to obtain the same data. Validation of the device is presented using over 50 different concrete mixtures with different workability, air void distribution, and combinations of admixtures. For 94% of the data investigated the SAM agreed with the ASTM C 457 hardened air void analysis. The SAM provides a valuable tool for contractors, producers, and owners to determine and evaluate the freeze thaw durability of concrete before it is placed. This is a tool that has the potential to greatly improve the durability and sustainability of concrete pavements.

When transverse cracks meander there is a high possibility for transverse cracks to meet at a point and connect to another transverse crack, creating a Y-crack. Y-cracks have been blamed for being the origin of punchouts and spallings in Continuously Reinforced Concrete Pavements (CRCP). When the direction of maximum principal stress changes, it could cause a change in the crack direction, potentially forming a Y-crack. In this study, finite element model of CRCP using typical Oklahoma CRCP pavement conditions and design was assembled. The model included the concrete pavement, asphalt concrete subbase, and soil subgrade. A localized change in friction between the concrete and supporting layers was modeled to determine how subbase construction uniformity could affect y-cracking. The effect of areas of changed friction on the direction of principal stress was simulated by considering a patch at the pavement-subbase interaction. Investigated factors related to this patch were friction coefficient between patch and subbase and patch size. A change in the friction had a large effect on the stress magnitude and direction of principal stress, leading to Y-cracks.

The local calibration of the performance models in the new mechanistic-empirical pavement design guide is a challenging task, especially due to the lack of needed data. For the selected set of pavement sections for local calibration, the data requirements include (a) a wide range of inputs related to traffic, climate, design and material characterization, (b) a reasonable extent and occurrence of observed performance data over time. In addition, to data limitations, the conventional statistical methods of split sampling for model calibration and validation further add to these complications. In the traditional approach about 70% of the data set is used for calibration and remaining 30% is utilized for validation. However, most of the States have a limited number of identified pavement sections for local calibration. Therefore, there is a need to employ statistical methodologies that are more efficient and robust for model calibrations given the data related challenges encountered by state highway agencies. In this paper, the rigid pavement cracking model was calibrated using the traditional and advanced statistical resampling approaches like jackknifing and bootstrapping. Jackknifing and bootstrapping methods provide more reliable assessment of the model prediction accuracy than the alternative methods. While traditional split sample approach use a two-step process for calibration and validation, advance approaches can simultaneously consider both steps. Moreover, the goodness-of-fit statistics are based on predictions rather than on data used for fitting the model parameters. The efficiency and robustness of such approaches become more important when the sample size is small. The results in the paper show the effect of different approaches on model parameter estimations and compare the role of such parameters in reducing the bias and the standard error of the cracking model.

Alkali-silica reaction (ASR) is a deleterious expansive reaction which occurs in concrete. The goal of this research is to extend the service life of concrete transportation structures (median barriers and pavements) effected by ASR through surface treatment mitigation. The goal was achieved through instrumentation and treatments of a concrete median barrier to measure strain and relative humidity. Strain was measured with detachable mechanical strain gages and gage studs embedded into the concrete. Relative humidity was measured with a portable probe inserted into the concrete. Surface treatments were applied to the concrete and included silane, linseed oil, and elastomeric paint. Results show that silane is effective at reducing internal relative humidity below the recommended threshold of 80 percent in concrete which exhibits minimal cracking. In concrete with moderate or severe cracking elastomeric paint is more effective at controlling expansion.

Since, the DARWin-ME is expected to be implemented by State DOTs for rehabilitation and new pavements analysis and design in the near future, it is important to highlight the practical issues related to the execution of these options. Several issues were encountered while executing the DARWin-ME rehabilitation options. These concerns are related to structural and material characterization of the existing pavement conditions. More specifically, the issues are related to: (a) characterizing the existing PCC pavement structure for unbonded overlays, (b) modeling of the HMA interlayer for unbonded overlays, (c) using backcalculated subgrade MR, and (d) utilizing Falling Weigh Deflectometer (FWD) testing. Typical PCC elastic moduli for existing PCC layers range between 3 and 6 million psi. For unbonded overlays, the elastic modulus is used to characterize the existing PCC condition. However, a limiting value of 3 million psi is suggested by the developers of the DARWin-ME. Counter intuitive results were observed when higher values of elastic modulus were used to represent field conditions. It was also found that the asphalt interlayer structural and material properties have insignificant effect on the equivalent PCC slab thickness. Furthermore, the current performance models in the DARWin-ME are calibrated using backcalculated subgrade MR values. Generally, the values are much greater than ones used for AASHTO 93 designs. In addition, DOT's cannot use the AASHTO 93 MR values in the DARWin-ME directly because the values are internally reduced by the software. Finally, because of critical impact of existing pavement conditions on the rehabilitation design, use of FWD to characterize the existing pavement structure has become more important. This paper documents the above mentioned issues and their impacts on pavement performance. Moreover, remedies are discussed to ensure reliable and accurate results by using the DARWin-ME overlay options.

Since 2008, New York City Department of Transportation (NYCDOT) has implemented red-colored bus lanes as part of its Bus Rapid Transit (BRT) program with New York City Transit (NYCT), and both agencies found that red treatment is effective at reducing unauthorized bus lane usage. DOT is seeking to improve the durability and cost-effectiveness of its preferred red lane treatment, and in 2010, began to research high performance red lane products and installation processes for different road surfaces. This paper presents the methods and findings from field and lab tests to evaluate red bus lane treatments for DOT. Field evaluations included long-term observations of various products used on bus-only lanes, as well as durability and skid resistance testing. Indoor tests assessed durability and skid resistance. Results indicate that a red epoxy-based paint, an epoxy with red aggregate product, and a red asphalt concrete-based micro surface performed well across all field and lab tests.

A field study was conducted to evaluate the effect of different installation parameters, namely, rout geometry, crack treatment type (rout & seal, clean & seal), overbanding, installation temperature and pre-installation pavement condition rating on the performance of crack sealants. Eight hot-poured crack sealants were installed in three test sites that experience low temperatures. The field performance of crack sealants was evaluated for two consecutive years by conducting detailed field surveys. The field database consisted of 38 sections containing a total of 487 cracks. The collected field survey data were used to assign a performance index (PI) to each sealant in this study. According to the preliminary results obtained from the field surveys within two years after installation, crack sealants installed in smallest rout geometry exhibited best acceptable performance among all the rout geometries. Sealants that were installed by the clean & seal method showed poor performance compared with their rout & seal counterparts on the same test section. On the other hand, overbanding showed improvement in the performance of crack sealants. Traffic volume and overheating of sealants appeared to deteriorate performance of sealants. Underheating of sealants and pre-installation pavement condition rating of pavement showed no clear trend on the performance of sealants.

Recycled concrete aggregate (RCA) is often used as a replacement or partial replacement of virgin aggregate. Commonly RCA is used in road foundations (base course), embankments, hot-mix asphalt, or Portland cement concrete. However the use of RCA in drainage systems, such as French drains, is currently prohibited in the state for Florida. The primary concerns with using RCA as a drainage media are the fines content and the precipitation of calcium carbonate to cause a reducing in filter fabric permittivity. Not much research has been conducted as it relates to using RCA as a drainage material; this limited information inhibits its use in French drains. This paper describes the investigation of permeability of RCA as a No. 4 aggregate gradation and base course gradation. The effect of excess fines (passing the No. 200 sieve) and the precipitation potential of calcium carbonate have also been studied.

The coefficient of thermal expansion (CTE) of concrete is greatly influenced by thermal behavior of aggregates due to their large volume proportion in concrete. In order to understand the effect of coarse and fine aggregate on the thermal behavior of concrete, the average CTE of concrete with granite and dolomite as coarse aggregate and granite-originated manufactured sand and alluvial natural sand as fine aggregate were measured. The results showed that concretes composed of high stone volume of granite with MS have the lowest CTE value (4.44μɛ>/°F) whereas those composed of low stone volume of granite with siliceous NS have the highest CTE value (5.42μɛ/°F). Testing results demonstrate that the effect of fine aggregate in concrete mixture is more dominant while using granite as coarse aggregate rather than dolomite. In addition, this study characterized the microstructure and chemical composition of both coarse and fine aggregates by utilizing petrographic analysis tools. Testing results were used to identify minerals showing varied thermal behavior and also to correlate with the measured CTE values of the concrete specimens so that better understanding of thermal expansion behavior of concrete could be made.

Under the study, "Improving FHWA's Ability to Assess Highway Infrastructure Health," FHWA sought to identify a means for assessing the health of the Interstate Highway System with a focus on pavements and bridges. In particular, the pilot study, Interstate 90 through South Dakota, Minnesota, and Wisconsin, evaluated methods to identify and validate approaches for categorizing bridge and pavement condition as good / fair / poor. The pilot study demonstrated that the good / fair / poor approach is not only feasible for pavements, but also implementable at this time using pavement roughness. Additionally, the use of the Highway Performance Monitoring System (HPMS) distresses was shown to be feasible, but additional work is required before they can be implemented. Accordingly, a continuation of the good / fair / poor development effort focused on pavement condition indicators including the HPMS distresses. The objective of the effort performed under the continuation was to develop a next generation pavement performance measure, which will enable the FHWA to more accurately and consistently assess the functional condition of portions of, or the entire, national highway pavement system. Based on project parameters, the measure was to consider ride quality and pavement surface distresses (cracking and rutting or faulting). In subsequent review of this objective, it was determined that reviewing condition in terms of each individual distress provided more reliable information than an index combining these data. In an effort to improve how these data would be used to assess condition, the following data elements were considered with regard to use of these data: ≤ Data collection ≤ Data processing ≤ Data quality control / quality assurance ≤ Data storage ≤ Condition rating Within this paper, we will explore these elements as they relate to ride quality.

Distress prediction models, or transfer functions, are key components of the Pavement ME Design and relevant analysis. The accuracy of such models depends on a successful process of calibration and subsequent validation of model coefficients in the transfer functions with independent data sets. In this paper, data needs for distress models in Pavement ME Design are investigated for the state of Oklahoma. Based on past research work at Oklahoma Department of Transportation (ODOT), various Pavement ME Design inputs, historical cracking, rutting, and roughness data are gathered for selected ODOT segments and Long Term Pavement Performance (LTPP) sites. Pavement ME Design test runs are performed, and precision and bias levels of rutting, cracking, and roughness data sets in the historical ODOT databases are studied. Finally a workflow for Pavement ME Design prediction model calibration in Oklahoma is recommended to assist ODOT in implementing Pavement ME in the coming years in a production environment.

Axle loading spectrum inputs obtained from existing Weight-In-Motion (WIM) stations are one of the key data elements required in the Pavement ME Design. Due to the limited number of WIM stations within a state agency, for Level 2 inputs for a particular design it is critical to implement clustering approaches to identifying similar traffic patterns and developing cluster average. Prep-ME, the final product of transportation pooled-fund study TPF-5(242), integrates four clustering approaches to generating traffic inputs for Pavement ME Design in a production environment. In this paper, the approaches are introduced and software capability to prepare traffic data inputs for a specific pavement design provided. The approaches include the discriminant analysis based method developed in Michigan, decision tree based method in North Carolina, the Truck Traffic Classification (TTC) method, and the simplified TTC approach. The first two methods were developed under separate research efforts and are implemented in software for production purposes in Prep-ME. The third method meets the needs for state DOTs that do not have a comprehensive clustering approach but have short term classification data for a design site. The last method can be used for less important secondary road based on engineering judgment without the need of any site-specific traffic data. It is anticipated that the Prep-ME tool can substantially reduce state DOTs' effort in calibrating and implementing Pavement ME Design in the coming years.

This study investigated the enhanced toughening characteristics of plastic fiber-reinforced hot-mix asphalt (HMA) mixtures in laboratory and field tests. The toughening effects of plastic fiber-reinforced HMA mixtures were characterized using direct tensile loading tests. Adding a small quantity of plastic fibers to HMA was found to significantly increase the mixture's fracture energy, which was calculated using the tensile force-displacement curves. The fracture energy model appeared to be governed by the direct tensile toughening of fiber-reinforced HMA's enhanced fiber bridging effects. The field measurement of the fiber reinforced mixture resulted in at least ten times lower tensile strains than those of the plain HMA at the bottom of HMA. This indicates that the fiber reinforced mixture has a superior field performance than the plain HMA does and can extend overall performance life of the mixtures if adding a small amount of fibers such as 0.4% by the mixture's weight within the context of the fiber developed in this study.

New emerging technologies in asphalt production and placement with the premise of saving fuel, reducing plant emissions, and extending the paving season into colder weather have been gaining popularity in recent years. These technologies, namely Warm Mix Asphalts (WMA), are produced by incorporating additives into asphalt mixtures to reduce the viscosity of the asphalt binders and allow aggregate coating at temperatures well below of those of the conventional hot-mix asphalts (HMA). Due to the short paving season in North Dakota, North Dakota Department of Transportation (NDDOT) has initiated WMA research in hopes that the use of WMA will lead to the extension of the paving season into colder weather. Also since previous WMA research was not conclusive on rutting and moisture issues, NDDOT constructed WMA and HMA overlays to evaluate the WMA resistance to rutting and moisture sensitivity. The WMA overlay sections were constructed using Evotherm 3G chemical additive. The primary purpose of the research study was to evaluate and compare the rut resistance performances of the WMA and HMA overlays under dry and wet conditions. Twenty four field core samples representing the WMA and the control HMA sections were selected and tested for rut resistance under dry and wet conditions using the asphalt pavement analyzer (APA). The APA results indicate that the average rut values for WMA samples were 13 percent and 29 percent higher than those of the HMA mixes under dry and wet conditions, respectively. The slight increases in rut values of the dry specimens were expected due to the reduced stiffening of WMA binders. On the other hand, the elevated rut values of WMA specimens under wet testing may suggest reduced durability of warm mix overlays.

One of the objectives of this paper is to evaluate the effectiveness of Nano-sized Hydrated Lime (NHL) modification on the creep and recovery behavior of foam-based Warm Mix Asphalt (WMA) produced using Advera®. Also, the study investigates the creep and recovery behavior at multiple testing conditions. NHL with a particle size of 50-nm and Regular Hydrated Lime (RHL) were added to the asphalt binder at the ratios of 5% and 20%, respectively. The creep and recovery behavior was investigated based on: 1) the Multiple Stress Creep and Recovery (MSCR) test, and 2) ten cycles creep and recovery proposed tests performed at different conditions: 3Pa (creep for 100 sec. and 600 sec. recovery), 10Pa (creep for 20 sec. and 600 sec. recovery), and 50Pa (creep for 1 sec and 300 sec. recovery). Advera® foaming slightly increased the non-recoverable compliance (J_nr) of the original binder. Adding NHL in smaller amounts can produce asphalt materials with improved creep and recovery behavior in comparison to RHL. Comparing the MSCR test and proposed creep and recovery methodology, the J_nr seemed dependent on the creep and recovery times.

Incorporation of used tires in asphalt mixtures has been a major advancement in the using recycled materials in asphalt pavements. Tires contain some of the polymeric components that have been used to modify the asphalt binders for decades, but in a solid form. This paper presents the result of a research to examine whether or not the proper application of the tire rubber in asphalt mixtures can enhance the pavement's mechanical properties to the same degree that the traditional polymeric binder modifiers do. The performance of a terminal blend tire rubber mixture was compared to a polymer-modified mixture through mechanical testing at the Asphalt Institute laboratory. Two mixtures in this study were designed with the same gradation in accordance with the California standard specifications, one with polymer, and the other with terminal blend asphalt. Flexural beam fatigue test, Superpave shear test, and disk-shaped compact tension test were conducted to evaluate the performance of the mixtures with respect to fatigue cracking, rutting, and low temperature cracking, respectively. The results revealed that the terminal blend mixture would have a better rutting performance. Furthermore, the terminal blend mixture exhibited a slightly more ductile behavior at the low temperature of -12°C. The two mixtures showed a similar performance with respect to fatigue cracking at 20°C.

The objective of this study is to evaluate the effects of existing pavement condition and overlay material property on asphalt concrete (AC) overlay design and performance. The newest AASHTO design software DARWin-ME was used to conduct the analysis under various traffic and structure combinations. The factors considered in the analysis include the modulus of exiting layers, the rut depth of existing layer, the interface condition between AC overlay and existing pavement, and the properties of AC overlay (performance grade and Poisson's ratio). In addition to overlay thickness design, pavement performance analysis was conducted to see the effect of existing pavement condition and overlay material property on individual distresses. Several findings were concluded from this study. First, the sensitivity of overlay design thickness to the condition of the existing AC layer depends on the existing AC layer thickness and design traffic. Second, the existing condition of base and subgrade has no significant influence to the overlay performance and design. Third, the performance analysis results indicate that the modulus of existing AC layer and interface bonding condition have more significant effects on fatigue cracking than on rutting potential.

The Rolling Wheel Deflectometer (RWD) is an innovative device developed for the efficient, high-speed measurement of pavement structural response over a broad network of roads. It uses a series of lasers mounted beneath the bed of a custom-built 16-meter semi-trailer to measure a continuous profile of pavement deflections produced by the trailer's 8,164 kilogram (kg) single axle load. The RWD has recently moved from a research prototype to a production tool that has been used for network level pavement structural evaluation. This paper presents the results of a study that evaluated the structural capacity of 463 kilometers (km) of Pennsylvania Department of Transportation's (PennDOT's) local and arterial roads using the RWD and a Falling Weight Deflectometer (FWD) and comparison of the results to the estimated structural capacity stored in PennDOT's Roadway Management System (RMS). The structural capacity determinations from RWD data were based on a methodology developed by the Asphalt Institute (AI) that correlated deflections from a Benkleman Beam testing device to remaining pavement life. The structural capacity estimates from the FWD were based on conventional techniques described in the 1993 AASHTO Pavement Design Guide. The RMS estimates are based on pavement composition and age data. The results of the study indicated a good correlation between the estimates of remaining pavement life from the three methods, although significant scatter was observed in the data. All three methods clearly distinguished between the structural capacities of three groups of roads with known differences in pavement strength. The study verifies that the RWD is a useful tool for network level pavement evaluation for planning purposes.

The Long Term Pavement Performance (LTPP) program has Specific Pavement Studies 5 (SPS-5), which study the effects of overlay rehabilitation on typical distresses. Each SPS-5sites has eight sections with two overlay thicknesses (50 mm and 125 mm), two overlay types (virgin asphalt mix and 30% recycled asphalt (RAP) mix), and Surface preparation prior to rehabilitation ( milling or not milling). The New Mexico SPS-5 sections are constructed in the eastbound Interstate-10 (I-10) in 1995. In this study, five distress parameters from these test sections are analyzed including International Roughness Index (IRI), rutting, fatigue cracking, longitudinal cracking, and transverse cracking. Analyses are conducted to determine which overlay factors affected the pavement performance more. Also statistical analysis is conducted to compare the performance of the No RAP and RAP mix. Analysis show that overlay age has the strongest impact on the overall pavement performance. Overlays with RAP showed more distresses and roughness than the no RAP overlays, although this difference is not significant for rutting and IRI. Also thick overlays perform better than the thin overlays except for rutting. Milling prior to the rehabilitation decreases IRI and transverse cracking, but do not have any effect on longitudinal cracking.

Due to the limitations of the elastic continuum theory, pavement engineers have recently paid considerable attention to the use of advanced modeling techniques for simulating the realistic behavior of asphalt mixtures. The objective of this study is to develop a three-dimensional (3D), heterogeneous model to describe the response of asphalt mixtures in the dynamic complex modulus test using an x-ray computed tomography (CT) image-based FE modeling approach. Experimental testing results for two Superpave mixtures including one conventional hot-mix asphalt (HMA) and one warm-mix asphalt (WMA) mix were used to validate and to calibrate the developed FE models. Adequate agreement between laboratory-measured and model-predicted dynamic modulus test results was achieved. Results of the developed FE models at different temperatures indicated that most of the deformations during the dynamic modulus test are derived from the mastic. In addition, asphalt mastic had more influence than the aggregates on the results of the dynamic complex modulus test.

Stone Matrix Asphalt (SMA) is a gap-graded asphalt rich mix with a high concentration of coarse aggregates. In the present investigation, SMA mixtures were prepared with chemically treated aggregates and Crumb Rubber Modified Bitumen (CRMB), and were compared for various characteristics. SMA samples were prepared in conventional Marshall and Superpave Gyratory Compactor (SGC) methods. Volumetric and Marshall properties, Indirect Tensile Strength (ITS), rutting and moisture susceptibility, fatigue behaviour and permeability characteristics were determined for these mixtures. From the laboratory studies it is evident that, chemically treated aggregates with normal bitumen (Viscosity Graded (VG) 30) and CRMB with normal aggregates can be used in SMA to meet the drain down requirements. CRMB mixes were observed to be having an upper hand in performance, even though treated aggregates mixes showed better moisture resistance properties.

SIDRA tool enables researchers and practitioners to model vehicle emissions at a project level. Vehicular fuel consumption and emissions performance (CO2 and CO) are simulated within single-lane roundabouts, with a one approach slip lane, under yield and free-flow exit control scenarios. Results are then compared to a roundabout with no slip lane, as a base, and all-way stop-controlled (AWSC) intersection within this experimental assessment. The MOVES (Motor Vehicle Emission Simulator) from EPA used to validate no slip lane roundabout as a base scenario. Results show that with a free-flow slip lane exit type, overall average total roundabout fuel consumption was reduced by 26%, CO2 emissions were reduced 27%, and CO emissions were reduced 17%, compared to an AWSC intersection. As expected, results indicate that a roundabout with and without slip lane shows a more significant reduction (improvement) of fuel consumption and pollutant emissions values than an AWSC intersection. Hence, the most effective roundabout performance in reducing delay, fuel consumption, and pollutant emissions generally is obtained from a free-flow slip lane.

This paper introduces a decision problem to evaluate when a single-lane roundabout incorporates a slip lane. Considers six origin-destination (O-D) traffic matrices that represent experimental of different unbalanced flow scenarios (traffic flow into and out of different roundabout approach is different) for a range of volume levels (low, moderate, and high). Performance of single-lane roundabouts with a slip lane is evaluated, based on the calculated roundabout average delay and the 95% queues results, using SIDRA under two control scenarios: yield and free-flow and results are compared to a roundabout with no slip lane. Slip lane right-turning traffic volumes range from 50 to 500 vehicles per hour. Results indicate that a free-flow slip lane exit type provides significant reductions in total roundabout average delay and the 95% queues and can be presented, and perhaps more efficient way, as the best alternative using a decision tree diagrams.

Safety performance functions (SPFs) are a required input to the newly released SafetyAnalyst software tool. Using statistical goodness-of-fit measures and visual plots, this paper compares the performance of locally calibrated SPFs using Florida data with the default SPFs from SafetyAnalyst for both freeway interchange influence areas and basic freeway segments. SafetyAnalyst defines an interchange influence area as one that extends 0.3 miles upstream and 0.3 miles downstream of the respective gore point. Using four years of local crash data (2007-2010) from Florida, SPFs for both types of segments for both urban and rural areas were developed using the negative binomial (NB) regression model. The results showed that Florida-specific SPFs generally produced better-fitted models than the calibrated SafetyAnalyst-default SPFs. This was clear in that the majority of Florida-specific models had higher Freeman-Tukey R-square (R²_FT), as well as lower mean absolute deviance (MAD) and mean square prediction error (MSPE) estimates.

The focus of this research project was to understand the extent of wrong-way driving (WWD) incidents on Central Florida toll roads by analyzing WWD data. The universe of WWD data contains many sources on both reported and unreported WWD events. Various WWD data sources were analyzed, including crash reports, citation data, and 911 call data to determine WWD trends and areas of high occurrence. A Computer Assisted Telephone Instrument survey was conducted on 400 randomly selected toll road customers that either personally witnessed WWD or knew someone who had witnessed WWD on Central Florida highways. These customers were asked about the details of this WWD incident, if it affected how they drive, and if they reported it by calling 911. The intent of this survey was to capture information about unreported WWD events to determine the full extent of the WWD problem and understand how toll road users react to WWD and want to be alerted about it. The analysis results were used to create a systematic ranking of Central Florida toll roads with respect to WWD. The rankings indicated that SR 408 and SR 528 (in this order) are the worst roads with respect to WWD. The results indicated that WWD is a problem in Central Florida that requires attention. In addition, the survey showed that many people do not report WWD, so it is important to detect and warn drivers about WWD. In order to improve detection and reduce WWD incidents, a Phase-2 study will evaluate various WWD countermeasures to determine which are most effective for Central Florida toll roads. These countermeasures will include low-cost and medium-cost improvements and technologies

In the United States, young drivers (16-24 years) are overrepresented in crashes when compared to experienced drivers. When looking at the methods of improving road safety of young drivers, it is important to identify the determinants of higher crash risk. The study described in this paper investigated the effect of various driver-, vehicle-, crash-, and environment-related factors and contributory causes on young driver crash risk using police-reported crash data from Kansas during 2006-2009 time period. Odds Ratio (OR) analysis was carried out using binary logistic regression to identify factors over-represented in young-driver crashes as compared to experienced drivers. According to calculated ORs with 95% of confidence intervals, it was seen that young drivers were more likely to be involved in crashes when driving with an invalid license, driving without wearing seat belts, driving at night, during weekends, on wet roads, or gravel/brick-tops. Results further showed that young drivers were overrepresented in intersection-related crashes or runoff-the-road crashes as compared to experienced drivers. Also, they were more likely to be involved in crashes due to failure to yield right-of-way; disregarding traffic signs/signals; turning or lane changing, improper action, aggressive driving; and some other driver contributory causes, compared to experienced drivers. Based on identified overrepresented factors and contributory causes, countermeasure ideas were suggested to improve safety of young drivers.

Construction of the bypass lanes at rural intersections has usually been considered as a low cost way to improve safety. Crash Modification Factor (CMF) is an acceptable measure for evaluating the safety effectiveness of a countermeasure, which is defined is the expected number of crashes with a countermeasure divided by the number of crashes expected without the countermeasure. This study evaluates the use of case-control method to estimate CMF for safety effectiveness of construction of bypass lanes at unsignalized rural intersections in the state of Kansas. In addition to looking at number of crashes at each intersection, this study evaluated the changes in crash rate and crash severity at intersections with the bypass lane versus intersections without it. Crash data were obtained for more than 700 rural unsignalized intersections from Kansas Crash Database which is maintained by the Kansas department of Transportation (KDOT) for the years 2009 to 2011. The paper concludes that the expected number of crashes is lower at intersections with bypass lanes in comparison to intersections without bypass lanes, while it has no significant effect on reducing crash severity.

Analysis of accidents at railroad grade crossings has traditionally been focused on developing models to determine overall trends from a large number of locations over time. While this approach results in models that can provide significant information at the macro level, it may not capture factors that can be only observable from a microscopic perspective. This paper uses a simple micro approach to enhance the analysis of accidents at railroad grade crossings. Trends identified in the microscopic analysis are based on detailed accident information such as location and direction of vehicles and trains, crossing layout and its surroundings, and driver demographics, among others. A micro analysis provides a different perspective on the selection of items to be improved and on the identification of crossings for funding allocation. Examples of micro analysis on two crossings in Illinois highlighted trends on the direction and location of accidents, potentially related to crossing angle and an interconnected intersection; and trends on the driver population and nearby housing facilities. These results could not be obtained using standard macro models alone.

Heavy vehicles, considering their size and low rate of acceleration and/or deceleration in traffic stream, are responsible for numerous negative effects on other vehicles. As a result, the capacity of signalized intersections declines significantly as the ratio of heavy vehicles in traffic flow is increased. In literature, there are different methods that are used with the goal of determining those negative effects. HR (Headway Ratio) is one of the most frequently used methods amongst all other methods. In this study, HR method was extended by substituting independent probability combinations set of vehicle types for percentage (%) of heavy vehicles in heavy vehicles adjustment factor F_HV equation. Also, four independent car-following combinations probability were considered: heavy vehicle following passenger car (H-C), passenger car following heavy vehicle (C-H), passenger car following passenger car (C-C), and heavy vehicle following another heavy vehicle (H-H). Probabilities of occurrence of each combination for percentage (%) of heavy vehicles were calculated by using the Bayes' theorem. The comparisons of results with different studies indicate that there is a significant difference between suggested new model and other studies on high heavy vehicle ratio condition. Moreover, the results showed that the proposed new model may give more accurate results being used in the intersections with high ratio of heavy vehicles.

This paper quantitatively evaluates the field performance of the SynchroGreen adaptive signal control and compares it to the performance of the conventional Time-Of-Day (TOD) signal timing patterns. The evaluation was conducted in terms of the signal parameters (e.g. cycle length and phase splits) and the traffic performance measures such as travel times, volumes, occupancy rates, and spot speeds. A SynchroGreen system was recently deployed at nine intersections on Glades Rd in Boca Raton, Florida. ATMS database, BlueTOAD database, and Sensys database operated by the City of Boca Raton Traffic Management Center were used to collect the data. Findings from the analysis of signal timings showed that the SynchroGreen was able to effectively cope with variations in traffic demand, both on hourly and daily levels. Regarding the traffic performance measures, SynchroGreen reduced travel times in the range of 2.4 % and 8.6 % in three out of four considered segments. In addition, the average occupancy rates and the spot speeds at the few instrumented intersections have improved, thus indicating that SynchroGreen performed well. However, not many of the improved performances were statistically significant. Further research is necessary to investigate how SynchroGreen performs in high-traffic conditions and during special events.

Intermittent queue conditions may happen due to stochasticity in arrival or departure rate. This paper develops INTQ which is a mesoscopic simulation approach to estimate intermittent queue length and delay. In INTQ, traffic is divided into groups with different sizes. The minimum group size is one for single free flowing vehicles, and it is more than one for platoons of vehicles. Each group has certain characteristics, such as size, inter-group gap, and average speed that are generated from statistical distributions. Once a group is generated, it moves in the network under some rules, called Group Following Rules. The INTQ methodology is presented and applied for a work zone and simulation results are compared with field data.

Traffic signal timing at signalized intersections with high pedestrian volumes and/or pedestrian safety concerns may include an exclusive pedestrian phase (scramble phase) to safely accommodate pedestrian demands. However, an exclusive pedestrian phase could be a significant source of delay for other modes because all vehicular movements stop during the scramble phase. Better understanding of pedestrian behavior at locations with scramble phases may lead to more efficient signal timing for other modes, while accommodating pedestrians. This paper studies pedestrian behavior based on field data collected at a busy intersection with a scramble phase on a college campus. Individual and groups of pedestrians were analyzed along with their ability to cross at free-flow speed to determine their behavior. Results indicate significant differences in combinations of these categories. 15^th percentile speeds for the diagonal and the parallel crossings (4.37ft/s and 4.49 ft/s) were higher than the 3.5 ft/s as recommended by the MUTCD. 15^th percentile speeds of pedestrians traveling individually and those in free flow were significantly higher than those traveling in groups and in non-free-flowing conditions. The average speed of individuals in free-flow conditions was not significantly different for parallel crossings but was significantly different for diagonal crossings. In addition, considerably fewer pedestrians crossed diagonally during the clearance interval than along the parallel.

Traditionally the Utah Department of Transportation (UDOT) has used traffic management specifications that only allow lane closures and roadwork to be done during predetermined hours or specifications that require a certain number of lanes to be open at all times. Recently mobility-based performance specifications have been considered, which could give the contractor more flexibility in construction work scheduling and maintaining an acceptable level of traffic flow. If the acceptable level of traffic flow is not maintained, the contractor is assessed a financial penalty at a predetermined condition. To discuss issues and develop guidelines a task force consisting of representatives from UDOT, the construction industry, and researchers from Brigham Young University was formed. Through task force meetings a set of guidelines were developed. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to find best approaches to deal with some of the complex issues.

Signalized arterials that support heavy commercial and business activities such as 34^th and 42^nd streets in Manhattan, New York City and heavy tourist activities such as South Las Vegas Blvd, Las Vegas attract large volume of pedestrians along with heavy vehicular traffic. Thus, some signalized intersections along such arterials and grid systems that accommodate heavy vehicular and pedestrian traffic may fail to operate safely and efficiently; which in turn may create congestions that may propagate onto entire arterial or grid system. As appropriate, this study proposes that pedestrian crossings at such intersections (targeted intersections that have significant pedestrian and vehicular conflict) should be eliminated while facilitating pedestrians to cross at midblock locations by installing pedestrian signals. Where pedestrians cannot be accommodated at midblock due to a shorter roadblock, they may be accommodated at other existing neighboring intersections where safety and operations are less critical. A sub-network including 34^th street signalized arterial in Manhattan, New York City is modeled in CORSIM with a target of eliminating pedestrians at 8^th avenue and 34^th street intersection. It is found that such an option (e.g., midblock pedestrian crossings) conditionally improves traffic operations and thus may improve air quality and reduce fuel consumption. Moreover, by eliminating pedestrians at high accident signalized cross walks and accommodating them at midblock on a pedestrian signal should improve pedestrian safety. The other advantage is that such an option still accommodates pedestrians at the street level rather than at over or underpasses.

Road is the dominant mode of transport in Bangladesh and the road accident rate in Bangladesh is much higher than those of the developed nations. Moreover, road accident has been steadily increasing over the years -- even exceeding the rates in other developing nations. A study based on over 3500 police reported fatalities per year conservatively estimates that the annual economic loss resulting from road accident is well over US $850 million or approximately two percent of the Gross Domestic Product (GDP). Nearly 50% of the total road accidents occur on National and Regional Highways that have a combined length of 7893 km. The severity of accidents on those roadways is much higher than those of the city and other roadways. However, the government of Bangladesh has been failing to formulate sound policies, and implement targeted programs and projects to improve road safety mainly due to fiscal budget deficits (funding shortage) for a sustained period. The fiscal budget of Bangladesh government has two parts namely revenue and development. The development budget, a large share of it is dedicated to infrastructure development projects, comes from the government and international development partner (e.g., World Bank, Asian Development Bank etc) sources. There was never an adequate fund in the national budget to address the road safety issue effectively. Moreover, often road operations improvement and maintenance projects are considered as an indirect investment on road safety. However, without the establishment of a dedicated and sustainable fund, articulation of the visions and development of targeted road safety programs and projects is nearly impossible. This study highlights the road safety issues in Bangladesh and proposes that suitable revenue sources to be used to establish a dedicated fund for the road safety improvement programs and projects. It also recommends that, in conjunction with the dedicated fund, other road safety financing options/tools such as public private partnership and debt based finance from the expatriate's remittance source need to be considered to improve road safety in general and particularly on national and regional highways, which are managed by the Roads and Highways Department, an entity under the road division of the Ministry of Communications.

Pedestrian movement highly influences the traffic operation in the entire road network, meanwhile pedestrian safety issues have been more considered nowadays. Pedestrians' behaviors include "crossing" and "walking", both of which interact with motorized vehicle mode. As one of the main traffic crash types, it is necessary to analyze the factors that affect the severity of pedestrian injury of a Pedestrian-Vehicle Crash (PVC) and differentiate them from "crossing" and "walking" pedestrian behaviors. Pedestrian, driver, vehicle, environment, and crash characteristics in specific PVC event are discussed. Ordered Probit models are developed in both scenarios to reflect the influencing factors of pedestrian injury severity in PVCs in terms of crossing and walking behaviors. Data from 2008 FDOT crash database are used to build such predictive models. Given the models themselves with the similarities and differences in two scenarios, suggestions and countermeasures based on findings will be provided to reduce pedestrian injury severity along with crash occurrence in order to improve pedestrian safety level.

Nationwide, more than 47,000 pedestrians were killed between 2000 and 2009, representing about 12% of the total highway traffic fatalities. In addition, nearly 700,000 pedestrians were injured over the same period. In Florida, one in every five traffic-related fatalities is a pedestrian, making pedestrian safety a top priority for safety improvements. This paper focuses on the analysis of pedestrian safety at signalized intersections. Since pedestrian crashes are rare and often severe, mere analysis of pedestrian crash summary records is not adequate. The underlying pedestrian crash patterns and causes were identified by reviewing police reports. During 2008-2010, police reports of a total of 2,951 pedestrian crashes that occurred at signalized intersections on state roads in Florida were reviewed. The review focused on collecting detailed crash specific information, such as identifying at-fault road user, presence and type of crosswalk at crash location, etc.

Teaching systematic safety analysis in class has been difficult due to the amount of data that needs to be collected. A database was created for a case study to demonstrate a systematic safety analysis in class using SafetyAnalyst. With the crash, traffic, and roadway segment data provided by the Utah Department of Transportation SafetyAnalyst was set up using highways in Utah County, Utah as an example. Approximately the top 100 segments were flagged as high safety concern. Two of these segments were selected to demonstrate in class how SafetyAnalyst's diagnosis and countermeasure selection tools could be used.

A number of steps have been taken over the past several years to advance the Utah Department of Transportation safety initiative. Previous research began the development of a hierarchical Bayesian model to analyze crashes on Utah roadways. The model analyzes roadway segments and determines a posterior predictive distribution of crashes. The actual numbers of crashes for each segment are compared to the predictive distribution and a percentile is calculated. A high percentile indicates more crashes than would be expected and a low percentile indicates less. A Geographic Information System (GIS) framework was developed to facilitate the analysis. The GIS framework has the capability to format the raw data such that it can be read into the statistical model. The GIS framework also displays the numerical data output by the statistical model spatially, allowing for an easy and intuitive analysis of `hot spots' or `black spots.' The purpose of this paper is to outline the GIS framework for crash data analysis, the results of which can be used to further evaluate those segments classified as hot spots.

Fractals are irregular geometric objects that exhibit finite details at all scales, and when magnified, their basic structures remain the same regardless of the scale of magnification. The main strength of fractal analysis is in its ability to find patterns in large and complex datasets. To benefit from fractal theory, a dataset must exhibit fractal characteristics. This paper investigates the existence of fractal characteristics in crash data from Florida using the fractal dimension and the Hurst exponent techniques. Using crash data from 1991-2011, it was found that the annual crash rate trend at signalized intersections exhibited fractal characteristics. Results of the annual crash rate analysis could be applied in the identification of high-crash intersections. For example, fractal analysis using the Hurst exponent technique could be used to predict crash trend and whether a high-crash intersection would continue to be on future high-crash location lists.

Faulting is an important performance indicator for jointed concrete pavements since it is highly associated with pavement ride quality. Currently many state DOTs have considered faulting measurements as a component of network-level pavement survey and used various instruments to collect faulting data such as fault meter, inertial high speed profiler, and newly developed laser based 3D technologies. The manual faulting measurement approach is time consuming, labor intensive, and presents potential safety hazard to operators and traveling public. For the inertial high speed profiler, the joint faulting measured at different lateral locations may be different as a result of the irregularities of the joint characteristics. Moreover, past studies indicated existing algorithms for automated joint detection and identification need to be further developed. In this study masking filter and the template match based algorithm are employed to locate the potential slab joints, and subsequently faulting at each joint is measured in accordance with the revised AASHTO R36-04 protocol. As a result, the slab joint quantity and locations identified using the proposed method is compared with that identified using the downward spike algorithm applied in ProVAL. Comparisons of the data indicate the template matched algorithm produces better identification results than the downward spike algorithm. The faulting validation would be made in the future research based on actual faulting measurements.

Automobiles, when traveling at a sufficiently high speed during wet weathers, can experience hydroplaning causing out-of-control accidents. Annually, 14% of all accidents with fatal victims occur on wet pavements. However, there were few research studies on detecting and identifying hydroplaning sections in a pavement network. This was primarily due to the fact that it was difficult and sometimes impossible to collect complete pavement surface data with geometric and geographical accuracies which are required to conduct texture, profiling, and cross slope analyses as the basis of hydroplaning studies. The advent of PaveVision3D Ultra technology, which is able to collect true 1mm 3D pavement data with complete coverage and at highway speed, makes it possible to collect and analyze virtual pavement surfaces at sufficient resolution for safety purposes. As a matter of fact, PaveVision3D Ultra is able to provide 0.3mm vertical resolution and 1mm resolution in x and y directions while the data vehicle is traveling at 60MPH. Coupled with high-performance Inertial Measurement Unit (IMU) data for geometric information, the collected 3D and position data sets are used to formulate a virtual pavement surface at high resolution for the proposed study. The hydroplaning velocity is a critical index to detect segments with aquaplaning potential; the influencing factors of hydroplaning velocity includes the tire characteristics, pavement subsurface structure, pavement surface characteristics, and rainfall intensity. Recognizing that highway with high speed limit and heavy traffic can lead to higher accident risk due to hydroplaning than other types of road, this study uses a section of interstate highway I-67S in Arkansas as the case study to present the pavement surface characteristics on hydroplaning evaluation. The significance of the presented data in the paper is three-fold. First, coupled with roll angles from IMU data, the collected 3D transverse profile data are used for cross slope calibration. Second, it integrates the real-time 1mm 3D surface data and IMU data into the Gallaway hydroplaning speed prediction model. Third, this method can identify hazardous locations with high hydroplaning potential so that pavement engineers may take remedial measures such as constructing superior grooving texture, posting proper speed traffic signs etc. to minimize potential traffic accidents.

Hartsfield Jackson Atlanta International Airport (H-JAIA) added a $ 1.4 billion New International Terminal, namely Maynard Holbrook Jackson International Terminal (MHJIT). During this project, the existing Automated People Mover (APM) tunnels were extended from west of Concourse E to MHJIT. The type of excavation was open cut, approximately. 70 feet wide and 50 feet deep, The excavation was supported by micro piles, soldier pile/timber lagging system & tie back systems and underpinning piers to a depth of approximately 50 feet below the existing grades. Movement and settlement of the existing test track tunnel and Concourse E was a concern due to unbalanced earth loads and existing foundations for Concourse E. Approximate length of new APM tunnel underneath Concourse E was 1200 feet and underneath Taxiway Dixie was 900 feet. To monitor the settlement and movement, Automated Total Stations (AMTS), Uni-axial & Bi-axial inclinometers were installed. Data generated by the monitoring systems were captured real time and used to provide early warnings and unexpected behavior of the structures associated with the new construction. The risk management program includes alarms generated from the system thru email when measurements exceeded the threshold limits and triggered a plan of action to avert any potential disaster.

Speed humps are known as the most popular traffic calming devices, although they transfer upward acceleration and forces to the vehicle which traverses them. These forces cause serious damages on vehicles and effect on passenger's discomfort. The main purpose of this paper is to investigate the vehicle's dynamic response to different type of speed humps via dynamic simulation modeling. Vertical acceleration, vertical force, and suspension force (spring force) were considered in order to study the vehicle's dynamic respond on speed humps. Totally, 90 simulation tests were run on a sedan passenger car and a typical truck (loaded) for 9 different hump's profiles. According to the results, ramp's length has the most effect on the dynamic performance of flat topped humps. Parabolic profile 3.65*0.1 (height=3.65m, length=0.1m) has the worst dynamic performance between all of speed humps. Also, sinusoidal profile seems to be a proper option from the viewpoint of hump's efficiency. However, it acts more vertical acceleration on vehicles in compare to all of flat topped profiles.

2D image-based crack detection has been studied for many years. But we are still short of a robust method, which can generate satisfied results on general cases. 3D pavement images have obvious advantages over 2D images in dealing with disturbances caused by lane markings, sun-light shadows, oil marks and debris. Taking advantages of the state-of-the-art 3D image acquisition technology, this paper proposes a novel crack detection algorithm. It has four steps: First, generate two partly overlapped images with 8×8 pixel grid cells. Second, extract 10 images of crack seeds through symmetry check and grayscale verification. Third, connect scattered seeds by an optimal path searching process considering grayscale values, cell direction and proximity. Finally, 10 detection results from two grid cell images are combined and denoised to obtain final results. Experiments based on 166 test images show that the proposed method can achieve better performance measured by F-measure, which takes both precision and recall rates into consideration.

Pavement roughness is the surface unevenness which adversely affects ride comfort. Basically, roughness is computed by measuring the vehicle suspension motion. It is expressed by International Roughness Index (IRI) with a unit of inch/mile or m/km. Roughness is very important information to the pavement management group, and maintenance and rehabilitation decisions are usually taken considering IRI and other distress data. Generally, transportation agencies do not collect IRI data annually for the entire roadway network because it requires a significant financial investment. Different types of tools are currently used to measure IRI, but these are either costly or inefficient. Recently, researchers at the Massachusetts Institute of Technology used accelerometers in cellphones to identify localized pavement defects. In the student presented herein it is shown that a smartphone based application shows great potential to capture pavement roughness as characterized by IRI. The IRI of a pavement section can be conveniently measured in a rapid and highly economical manner using this approach. In this study, three 2-mile long test sites were selected, where each having different levels of pavement distresses and roughness. IRI data was collected using an inertial profiler, and vehicle vertical acceleration data was collected using an android-based cellphone mounted on the dashboard of an inertial profiler van. Acceleration data was analyzed to obtain IRI for every 0.1-mile pavement section. Subsequently, acceleration data was collected from the same test sections using a passenger car. Results showed that the IRI estimated by the inertial profiler and cellphone application to be very similar. Results also compared favorably between trials conducted with the profiler van vs. the passenger car. Updated IRI data can be used to arrive at more effective pavement designs, maintenance, and rehabilitations decision making.

Concrete overlay has been long used as a promising and cost-effective approach for pavement repair compared to an entire pavement replacement. To ensure the quality and durability of the concrete overlay, US Department of Transportation (USDOT) suggests a minimum thickness of 5~6 inches for concrete overlay. For a cost benefit, thinner concrete overlays with sufficient strength are continuously investigated and a practical application of thinner concrete overlays needs field performance evaluation, which demands reliable infrastructure sensors. Traditional electrical sensors such as strain gauges and vibration wires, showed high electromagnetic interference (EMI), relatively short life cycle, and need corrections due to temperature variations and lead wires/connections are degraded by high humidity in the pavement environment. These disadvantages limit their reliability for long-term pavement performance monitoring. Optical Fiber Bragg grating (FBG) sensors, with unique advantages of compactness, are immune to EMI and moisture, capability of quasi-distributed sensing, and long life cycle, could be a potential candidate for long-term concrete overlay performance evaluation. However, the FBG sensors surfer from their fragile nature of glass materials to survive the concrete overlay construction process. In this study, to enhance the durability of the FBG sensors, glass fiber reinforced polymer (GFRP) is used to package material. The GFRP packaged FBG (GFRP-FBG) sensors are further applied to evaluate the performance of ultra-thin concrete overlay of 3 inches in thickness using fiber reinforced concrete materials, at MnROAD facility, Minnesota DOT (MnDOT). The design of the GFRP-FBG sensors, their field layout, field test setup, and data analysis are discussed in this paper. The performance of the ultimate thin concrete overlay in the first few months of service was evaluated accordingly. Upon validation, the GFRP-FBG sensors can be further applied for condition monitoring of any types of concrete pavements to assistant pavement maintenance.

3D design for highway and other transportation projects is ramping up in a significant way. However, almost all projects using this new technology still rely upon 2D mapping and occasional cross-sections or point locations for the depictions of existing underground utilities. The reason for this is simple; there has been no 3D utility information consistently and comprehensively available. Although the x,y data is pervasive, and reliable when ASCE 38 ("Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data") is utilized, the z values have been spotty and singular, or totally estimated from mostly unreliable sources or no sources at all. A convergence of improved geophysics developed by various international and national research programs (ORFEUS-EU; Mapping the Underworld - UK; Strategic Highway Research Program -USA) are combining with new ASCE concepts on z-value risk management attribution to address this problem. Florida DOT has instigated a trial program to utilize these technologies and concepts on a variety of highway projects. This paper will detail the technologies, processes, and risk management aspects of 3D mapping of non-visible assets, and results so far of the successful project deliverables for the Florida DOT. It will discuss remaining challenges and issues, and the potential to leverage clash detection programs based upon good data versus bad.

Technology Transfer (T2) centre is a repository for information about technologies and resources from appropriate technology to good practice. Despite the availability of numerous transportation technologies and innovative practices developed in various countries, much of these are not known outside the country of development. The objective of this paper is to discuss the innovations and strategies adopted in the establishment of T2 centre in Botswana to train and develop transportation engineering professionals. The Establishment of Botswana Transportation T2 Centre came to reality in June, 2004 as a tripartite arrangement between the Ministry of Transport and Communication; the Faculty of Engineering and Technology, University of Botswana; and the Federal Highway Administration (FHWA) of the United States of America. The mission of the centre is to improve the quality of transportation by having a well-maintained and an efficient transportation system through dissemination of highway technological information and training of both stakeholders and road users. Aims and objectives of the Botswana T2 centre is to facilitate technology transfer through dissemination of relevant best practice in all aspects of transportation; promote research and training of professionals in the transport sector; enhance traffic safety and public welfare of transport users; foster economical, efficient and environmentally sound transportation systems. In conclusion, the paper highlighted the outcome of establishing T2 Centre to train and develop transportation engineering professionals through improved technology transfer activities and beneficial uptake of the practice in transportation technology leading to a more efficient and competitive transportation system.

This research has been conducted to discover the correlation between side friction factor (demand) and longitudinal grade which is located in horizontal curves in three-dimensional simulation model. In this way, we present a series of models in order to assess these factors based on design speed, longitudinal grade, and vehicle type (Sedan, SUV, and Truck). The research involves (1) conducting a series of multi-body simulation tests using CarSim and TruckSim, (2) multiplex regression analysis to acquire relations between variables, and (3) recommending models for the side friction factor. Based on the results, side friction factors (demand) are bigger than downgrades for all vehicle types when cornering. Another important result is the significant differences of side friction factors for passenger cars in compared to heavy vehicles.

Over the last couple of decades there has been an increased contribution of the private sector to finance infrastructure projects. However, in view of the current global financial crisis, it has become more difficult for governments, particularly in transition and developing economies, to attract private financing for infrastructure, which may affect negatively the capacity of many countries to expand, and even keep up their infrastructure. While this is an observed short-term phenomenon, it is still not clear what will be the medium to long term effect of the crisis. It may well be that governments may be willing to increase their financial support to infrastructure projects so as to make them more attractive to potential private investors. This paper focuses on availability payment (AP), which has been increasingly used to undertake critical infrastructure projects in both developing and developed countries. It presents the development of a user-friendly tool for financial assessments of availability payment PPP projects. The model is suitable for preliminary assessment and screening of potential PPP projects. The applicability of the tool is demonstrated through a numerical example of a potential road PPP project. The model can also be applied to any other mode of transport or infrastructure. The model can be used to carry out sensitivity analyses. The user can change the value of an input parameter (e.g., construction cost) and obtain the resulting impact, for example, on the project financial internal rate of return.

Estimation of time duration of highway projects at the planning stage serves as a vital input for construction planning, scheduling and contract administration. However time overrun, resulting from various factors is the most cardinal issue which eventually leads to cost overrun and hence induces turbulence in the initial cost and time estimates. In this paper, highway project duration is estimated on the basis of variables such as planned cost and project type which are known at the planning phase. Data comprises of project types such as pavement construction, improvement, rehabilitation and bridge construction projects of National Highway Authority, Pakistan. A mathematical relationship between highway project duration, planned cost and project type is demonstrated in this paper by using various model specifications. Furthermore using multivariate regression analysis correlation of the time overrun with potential risk factors is investigated encompassing attributes such as project type, cost and geographical location. This paper identifies a number of significant risk variables and their severity that contributes to the extensive delays and consequently exceeds the planned time estimates. The models developed can assist the project administrators in determining improved estimates of project duration and enhancing the expected delay estimation in completion time of planned projects.

The transparent practice of involving stakeholders in the decision making process can largely aid in eliminating opposition against sensitive and highly-debated transportation projects. Multi-Criteria Decision Analysis (MCDA), in particular, is able to consider opposing points of view of multiple stakeholders. This paper presents the research done in the realm of MCDA with the objective of identifying the appropriate technique within MCDA process that can best aid in building consensus among stakeholders. The work is done by examining a number of widespread techniques used at each MCDA step through its application to real-case study. Assessing stakeholders' perceptions of each of these techniques is conducted throughout the analysis process. After presenting the case study decision context and the application of the MCDA techniques results in detail, the paper concludes with matrix recommendations for building consensus via MCDA. The research finds weight elicitation via pairwise comparison, scaling via modeling and utility function, and amalgamation via the probabilistic impact index method perform best with regards to providing confidence and building consensus among stakeholders.

The Transportation Performance Index (TPI) provides a snapshot of the performance of transportation infrastructure in a specific year based on indicators reflecting supply, quality of service and utilization. To better understand how the TPI changes with investment, regional long range transportation plans were reviewed and the impact of the proposed investments estimated for 2035. Without investment, the performance of transportation infrastructure, as measured by the TPI, declines significantly from 2011. With investment the TPI is shown to increase significantly, underscoring the importance of these strategic investments.

The Port Authority of New York & New Jersey is responsible for a wide variety of transportation infrastructure serving the New York/New Jersey Metropolitan Area. The Agency's Engineering Department has long established guidelines for infrastructure design. Following Super Storm Sandy, the Agency's leadership directed a multidisciplinary review of its Design Guidelines to see if changes were required to improve infrastructure resiliency to severe storms and future climate conditions. This review resulted in the development of a new addition of the Port Authority's Design Guidelines. The new guidance includes considering the probability of the event occurring (storm surge, precipitation, high or low temperature, etc.) during the design life of an asset when establishing project specific design criteria. Facility specific 1% probability flood maps, which incorporate sea level rise projections, were also developed. In addition, detailed items were updated to reflect the climate projections and in some cases this criteria exceeds the requirements of current codes. This paper describes the changes made to the Port Authority's Design Guidelines for transportation infrastructure resiliency.

There has been a paradigm shift in focus from intersection-level to corridor-and area-level analysis and performance measures in recent years. The possibility of capturing dynamic and continuous travel time and/or speed data from private sources such as INRIX opens many pragmatic avenues to predict reliability of transportation systems. Travel time reliability (or index or variability) is considered the most viable performance measure for corridor-level analysis though it is not being widely used for transportation planning, project prioritization, and allocation of resources. The definition of reliability as a performance measure and associated thresholds to understand or assess transportation system performance could vary for a link, corridor or an area. These definitions and thresholds to assess reliability need to be clearly established prior to its large scale application. This research aims to fill this gap by computing, comparing, and assessing link-, corridor- and area-level reliability measures. Data for the city of Charlotte, North Carolina was used to compute reliability measures, examine temporal and spatial variations, and illustrate how reliability can be used for transportation planning, prioritization and allocation of resources.

Performance Measurement has become the new buzzword for transportation planning in the 21^st Century. The Federal Highway Administration (FHWA) defines Transportation Performance Measurement as a "strategic approach that uses system information to make investment and policy decisions to achieve national performance goals." Performance measures can be either quantitative, as in Vehicle-Miles Traveled (VMT) per capita, or more qualitative; as in, comfort of the transit vehicle or enhanced transit amenities at stations. Performance measures can also be applied at a variety of scales, including: the entire transportation system, a corridor, and/or even a specific facility. A measure such as CO₂ emissions is probably best measured at a systemwide scale or greater, while pavement conditions is probably best measured at the scale of a particular facility. Performance measurement has attained heightened importance as the most recent federal transportation reauthorization bill, "Moving Ahead for Progress in the 21^st Century," (MAP-21), is requiring the United States Department of Transportation (USDOT), in consultation with State DOT's, to develop Performance Plans based on specific performance measures and targets for many of its transportation programs, or risk losing funding. In times of fiscal austerity such as these, as well as increased cynicism about the role of government, officials at all levels of government must pay increasing attention to how and where each public dollar is allocated, and what type of performance outcome it generates. Just as shareholders expect good performance from public corporations for which they hold stock, taxpayers are holding decision-makers more accountable for how their funds are getting spent. The best and most expedient method to ascertain this public "Return on Investment" is through Performance Measurement. Following a description of performance measurement and why it's significant, this paper will examine the different types of performance measures being utilized by transportation agencies nationwide. Different agencies may have different measures depending on their goals and missions. Further, different types of infrastructure assets may also have different measures. For example, a transit agency will likely have average daily ridership as a performance measure; and is less likely to have a measure such as volume-to-capacity ratio, which is more likely to be used by highway agencies as it measures road and highway performance. Similarly, a bicycle advocacy group is more likely to be concerned about specific indicators of bicycle level of service (LOS), as opposed to a highway agency that is more likely to be focused on roadway conditions and motor vehicle throughput, (although with the advent of "Complete Streets" principles adopted by many agencies nationwide, performance measures that at one time were exclusive to one mode are being shared by numerous agencies and measures are becoming multi- modal). The paper will conclude with some best practices of performance measures, including those used by DOTs and Metropolitan Planning Organizations (MPOs).

The Enhanced Integrated Climate Model (EICM) in the Mechanistic- Empirical (ME) Pavement Design software is an integral part of the ME pavement design process. EICM has a national weather database with hourly data from approximately 800 weather stations for at least 60 months. EICM uses the included historical hourly weather data to model future climatic conditions for accurate prediction of pavement distresses. Recently, many state departments of transportation started to enhance these weather station data by adding more weather stations and/or expanding the number of months of available data. The goal of these efforts is to utilize a weather station very close to the project site and include more historical weather data. In the ME Pavement Design software virtual weather stations can be created by selecting up to six weather stations to model climate change in the vicinity of the project site. However, without having extensive knowledge on regional climatic patterns, the pavement designer may not select the most appropriate weather stations to represent site specific climate conditions. Many states have microclimates due to different geographical or environmental conditions. This paper examines the use of Geographical Information System (GIS) to create a local climate zone map to aid pavement designers to select the most appropriate weather stations for pavement designs. Four climate zone maps were developed using the average low temperatures in January, average high temperatures in July, average precipitation in January and average precipitation in July for the I-94 corridor in Michigan as a case study. Further, the combined effects of these variables were examined by combining above individual climate zone maps into a single composite map using Inverse Distance Weighted (IDW) techniques. The maps show localized climate zones even within the same county highlighting the need of using appropriate weather stations to correctly model the climatic effects in pavement performance. The use of the developed methodology was demonstrated by comparing pavement performance results for a same pavement structure located in different climate zones using MEPDG software.

Ultra-thin bonded bituminous surface (UBBS or Novachip) is a preventive maintenance or thin surface treatment that consists of a thin, gap-graded hot-mix asphalt (HMA) layer applied over a thick polymer-modified emulsion layer. The Kansas Department of Transportation (KDOT) has been using UBBS since 2002 and some of these projects are now being rehabilitated. The main objective of this study was to evaluate the performance of UBBS projects in Kansas using distress data from the Pavement Management Information System (PMIS). It was found that pavements treated with UBBS showed high variability in service life with majority serving six years. Before and after (BAA) studies showed that UBBS reduces pavement roughness, transverse and fatigue cracking one year after the treatment. A sharp drop-off in effectiveness for mitigating transverse and fatigue cracking was observed after a couple of years in service. The analysis of variance shows that service life, cumulative traffic and existing pavement thickness are not significant determinants of progression of distresses.

The NJDOT is increasing the use of micro surface and chip seal earlier in the pavement life cycle to economically extend the service life of a pavement, to promote a high level of pavement condition index (PCI) throughout the state network, to provide functional benefits such as increased skid resistance, reduced splash and spray, and noise reduction. To determine if a noise reduction is attainable using these surface treatments, it was important to first measure the associated noise levels generated and determine how they compare to traditionally used thin-lift overlays. A tire/pavement noise evaluation was conducted utilizing the On-Board Sound Intensity Method (OBSI) on micro surface and chip sealed sections that were placed on state-maintained roads as test sections to compare to noise levels included in the NJ noise database for ultra-thin bonded wearing course (Novachip), High Performance Thin Overlay (HPTO), Stone Mastic Asphalt (SMA) and Asphalt Rubber Open Graded Friction Course (AROGFC). The rank order noise level of thin-lift overlays from quietest to loudest ascertained from this study was AROGFC, SMA, HPTO, Novachip, and then micro surface.

Traditional civil engineering practice methods are primarily focused on publishing construction documents to support project delivery. However, even with the internal design processes in most engineering organizations having been fully digital for at least the last 10 years, most of the time and energy spent in engineering is consumed by the preparation of analog, traditional format documents to communicate the plans, specifications, and estimates instead of the designs themselves. The recent MAP-21 transportation funding law, passed in 2012, contained a game-changer for these legacy practices. It mandates the gradual introduction of advanced digital modeling in the delivery of all federally-funded transportation projects from planning, through design, and all the way to construction, and provides for additional federal funding for those projects that implement these innovations and program efficiencies. The business case behind the language in this Federal law was discussed in a 2004 National Institute of Standards and Technology report, estimating that 40-60% of all engineering effort is consumed producing non-interoperable analog information. Many organizations and vendors have responded to this initiative by promoting several types of technologies, represented by an array of acronyms such as BIM, CIM, FIM, BrIM, VDC, IPD, 4D, 5D, AMG, etc. However, these technologies will prove to be ineffective if civil engineering practice methods aren't updated from an analog worldview to a digital worldview. The peak of optimistic expectations will fall into a trough of disappointment as the technologies by themselves fail to deliver any return on the investment. This presentation will address how civil engineering practice methods need to evolve to work effectively in this digital world, using both existing and emerging technologies to carry digital design information across the design/construction interface. These practices are already being implemented across the country on innovative design-build transportation projects on which engineers and contractors work for the same team, where they have significant financial incentives for innovations that save time and money and improve quality.

Flexible signal timing operation with cycle-free and sequence-free strategies using reinforcement learning has been researched from different fields and applied to transportation networks. Such techniques naturally rely on accurate incoming data for optimal operation. However, the effect of imperfect information received by RL agents in a traffic environment has not been explored in detail and may provide further indication to whether they can be truly suitable for real-world applications. This paper studies this topic in the context of a congested traffic network, where RL agents receive aggregated loop detector data to make decisions, instead of directly observing activations from all vehicles. A case study shows the sensitivity of the agents' performance when data is aggregated to different levels. Aggregation levels are used as a method to represent imperfect information, and the performance of the system is used as an indicator to determine acceptable aggregation for the system to remain operational in oversaturated conditions.

The Emirates Air Line is an innovative, urban and new transport link for London. It is the first urban cable car system of its kind in the UK, providing a unique river crossing linking two key destinations. The cable car is connecting with its 34 gondolas local communities, improves access to visitor destinations and speeds up river crossings. It will also encourage further regeneration at The Royal Docks and Greenwich Peninsula. Owned and operated is the cable car by Dockland Light Railway Limited (DLR) a part of the TfL network. Emirates is the Scheme Sponsor in a 10 years sponsorship deal. The operations is a unique partnership of world class companies. Each has committed to strive for the highest standards in its industry sector. The combined expertise of TfL, MaceMacro, Doppelmayr Cable Car, Continuum, CUK and Easy Clean is focused on making the Emirates Air Line a unique experience for London and not just a service.

The LYMMO bus rapid transit service, operated by LYNX Transit in Orlando, Florida, began in August 1997 as one of the first premium bus-based downtown circulators in the United States. The Center for Urban Transportation Research (CUTR) at the University of South Florida recently conducted an evaluation of the LYMMO to see how well it has performed for the last 15 years. The evaluation found that ridership quickly plateaued after 1997 and has fallen off since 2010. Nevertheless, the LYMMO still carries more annual passengers than several rail streetcars of comparable length and at a lower operational cost. Surveys of LYMMO riders and downtown employers revealed that a majority of respondents believe the LYMMO has reduced congestion in downtown Orlando, contributed to the economic development of downtown, and made downtown a more attractive place to live and work.

This paper takes another look at high-speed rail in the United States. Faster rail service will become more important as the nation's population grows, traffic congestion increases, and air space becomes more overcrowded. National interest in faster intercity rail service is growing, especially in corridors up to 400 miles. The paper explores various options for faster rail services that range from full-fledge high speed rail (HSR) with top speeds up to 200 mph to more modest speeds (HrSr) with incremental improvements to existing lines with top speeds up to 110 to 125 mph. It contains a level of service concept that is consistent with Federal Railroad Administration (FRA) track classes. Key factors that are essential for HSR and HrSr are discussed. They include markets, physical environments, costs, and public policy. The more promising projects have these factors mutually reinforcing each other. They have major anchors at both ends of a line, good intermediate markets, and suitable rights-of-way. Within this context, the paper identifies promising corridors. They include the HSR and HrSr corridors under development in California, the Northeast Corridor, and possible corridors in the Midwest, Florida, Texas and the Pacific Northwest.

Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria. However, while rail transport continues to enjoy relative importance in terms of investment, growth and contribution to the national economy in several countries, it has suffered neglect and relegation in Nigeria, resulting in a decline in its modal share contribution. Particularly, in the last decades following independence, not much has been achieved in terms of structural transformation of the Nigerian Railways. However there are new developments and investment on rail and some measures are being put in place to revive the Nigerian rail transport system. Old and unused railways are being modernised, rehabilitated, commissioned and brought into service. Therefore, it is vitally important to understand and analyse the performance criteria that can be applied in measuring and managing the Nigerian rail sub-sector. Currently this measurement criteria has not being established. The focus of this paper is on identifying Key Performance Indicators (KPIs) for the Nigerian rail sub-sector. The KPIs that has been identified in this paper following the performance measurement framework, can be used to measure the performance of the rail subsector and eventually guide the further development of rail transport in Nigeria, in the sense that the KPIs will assist in identifying key areas for improvement in the sector and also serve as a guide for transport policy makers in making decisions. The KPIs presented in this paper has been categorised into: Safety; Security; Environmental pollution; Internal Business perspective; Financial perspective; Intermodal perspective; Innovation and Learning perspective and Customer Satisfaction.

Preventing broken-rail-caused derailments is a high priority for the rail industry and government. The current practice is to periodically inspect rails using non-destructive technologies such as ultrasonic rail inspection. Determining the optimal inspection frequency is a critical decision in railway infrastructure management. The objective of this paper is to develop an analytical framework to address the trade-offs among various factors related to rail defect inspection frequency, in order to maximize rail transportation safety and efficiency.

The evolution of pedestrian flow analyses and modeling is continuing to progress from basic spreadsheet to rudimentary pedestrian simulation based on a grid system to newer tools that show people moving much more naturally. In any case, while the all of the analytical tools are essentially based on the foundation of Jack Fruin's 1960s pedestrian flow research, and later with Benz' time-space methodologies, software and computer technologies have advanced well past the point of rudimentary, perhaps even crude imagery. By now, the appetites of architects and engineers to examine the effects of their designs on pedestrian flows before such plans were constructed are rather extreme, fueled, in part, by the savvy public's access to internet sources. So on two fronts, designers cannot afford to construct inadequately designed terminals and stations because of the obvious funding issues and now to meet end-users' expectations. Our marquee project, one of the country's most visible, involves planning and designing the new transportation hub at New York City's World Trade Center site. Our use of static and dynamic tools is a requirement of our client to demonstrate that the agreed upon basis of designs will be achieved. But that work is now some five years out, and the advent of better software is here. The paper focuses on a number of concerns. First, briefly, how were these models developed? Second, what will the analyst see as realism? Third, what benefits accrue from the work involved to construct such a model? The results are quite dramatic, and having showed the basic model at other technical conferences, many in the audience inquired as to what the next steps were. The "next steps" are here.

Floating car method, technologies such as global positioning system (GPS) units or data from private sources such as INRIX are used for travel time data collection on urban streets. Time, man-power, and cost deter (limit) collection and purchase of such data for the entire transportation network. An alternate source of the travel time data is using buses as probe vehicles. This is practically feasible and inexpensive as most buses operating in urban areas are equipped with automatic vehicle location (AVL) units. However, the travel time of buses is generally greater than the travel time of a typical vehicle (car). The use or applicability could only be justified if there is strong correlation between car and bus travel times. This paper, therefore, examines the relationship between car and bus travel time. The role of key influential factors (such as the number of signalized intersections, the number of unsignalized intersections, the number of driveways, the number of bus-stops, traffic volume, the number of lanes and the number of turns made by the bus) on the ratio between the two travel times is also evaluated and examined to assess the use of buses as probe vehicles. Results indicate a moderately strong relationship between car and bus travel time. Variables other than the number of signalized intersections per unit distance, the number of lanes, and traffic volume do not seem to play a statistically significant role on the ratio of car to bus travel time irrespective of time-of-the-day. Models by time-of-the-day, developed to estimate car travel time, could be used if bus travel time, the number of signalized intersections per unit distance, the number of lanes, and traffic volume are known.

Innovative intersections are designed with dislocated left turn movements and reduced number of traffic signal phases in order to increase the capacity and reduce the number of conflict points. These intersections are considered as alternative designs in the future Transit Oriented Development (TOD) location in West Valley City, Utah, in order to resolve traffic congestion on the most critical network points. This study compares Median u Turn, Bowtie and Quadrant intersection designs to conventional intersection capacity expansion design strategies. Traffic and transit data were provided from the local agencies, and modeling was performed in microsimulation through static traffic assignment. Performance measures are compared on the intersection, corridor and network wide levels, for 2009 and 2040 forecasted traffic conditions from the planning models, calibrated using traffic volume data for 2009, for the PM peak period. Among the different intersection designs, innovative intersections performed better than the traditional expansion of intersection capacity. Network wide analysis consistently shows lowest delays for the Quadrant intersection design that also decreases total distance traveled, when compared to the other analyzed designs. Quadrant intersection has the potential to decrease Vehicle Miles Traveled (VMT), and with the design that supports street connectivity, can improve TOD potential of our test network, since it is both pedestrian friendly and provides opportunity for mixed land uses. This research is a part of an ongoing effort to examine unconventional intersection designs and their potential to support TOD environments.

Kansas City International Airport (MCI) constructed a majority of their Portland cement concrete (PCC) pavements in the late 1990's and early 2000's. Currently most of the PCC at the airport has durability related cracking (D-cracking) associated with poor aggregate properties. Runway 1L-19R is an un-bonded PCC overlay system constructed in 1998 with a significant amount of pre-existing underlying pavement structure. The original PCC pavement section was constructed in 1959 using 12-14 inches of concrete. Subsequent 6-inch asphalt concrete (AC) overlays occurred in 1968 and 1983. After 1998, the runway section consisted of 15 inches of PCC on 13-15 inches of AC on the original 12-14 inches of PCC. D-cracking in this overlay was originally witnessed at or around 2008 when Airport Operations began collecting debris from the runway, ranging anywhere from 1-3 inches in diameter. By 2011, the D-cracking was observed to have accelerated quickly on the runway and coincided with the increased usage associated with airline growth and mergers. The Kansas City Aviation Department (KCAD) performed concrete partial depth repair and panel replacement projects in an attempt to mitigate these distresses. However, as the D-cracking accelerated, Foreign Object Debris (FOD) became a daily challenge for Airport Operations to manage, with Operations collecting almost a 5-gallon bucket of debris per day. In 2011, with the runway not yet reaching the prescribed 20 year design life, KCAD decided to rehabilitate and considered numerous options. This paper will discuss both the operational and rehabilitation challenges associated with functional deterioration caused by the D-cracking on Runway 1L-19R.

Subgrade characterization plays a key role in the thickness design of airport pavements. From a mechanical point of view, a subgrade soil represents a highly diverse heterogeneous structure. The usual practical way to deal with heterogeneous composites is to average their mechanical properties over the material volume. In the current study, the particular soil parameters under consideration are Young's modulus E, subgrade reaction modulus k (k-value), and California Bearing Ratio (CBR). The Federal Aviation Administration's (FAA) FAARFIELD thickness design program embeds a simple mathematical correlation between k-value and CBR. This correlation is conservative in the sense of over-estimating the subgrade reaction for a given CBR value, which encourages designers to unnecessarily increase the design thickness of rigid pavements. On the other hand, the commonly used PCA conversion formula overestimates k-value. Both formulas are not reliable for low-strength soils. The objective of this work is to present an updated conversion formula relating the k-values and CBR for lower CBR soils. A new conversion formula is proposed based on the analysis of available plate load and CBR tests for a range of subgrade soils. Results are shown to be consistent with linear regression of experimental data obtained during tests in the FAA's National Airport Pavement Test Facility.

People living in cities and rural areas within one hundred mile radius from large international airports such as Dallas/Fort Worth International Airport (DFW), O'Hare International Airport (ORD), and Houston Intercontinental Airport (IAH) rely on their personal car, a taxi or shuttle bus to get to access those airports for travel to "long-haul" domestic or international destinations. Recently airlines have cut down on the frequency of operations or reduced their flights from regional airports. In some cases they have totally eliminated unprofitable flights to major hubs. Due to these changes in air service, residents up to 250 miles away from the major hub airports may no longer have a viable air link to the hub airports and may need to rely on ground service. This research details, whether a convenient, affordable and comfortable air service is viable for a specialized "short-haul" air service connecting the regional airports with a major hub airport. The analysis presents population forecasts for the counties and cities and air travel demand forecasts for the airports. Historical air carrier operations, number of arrival and departure seats, past air fare data for each of the regional airports is obtained from the FAA data base and Bureau of Transportation Statistics (BTS). In addition, fuel price, parking rates, landing fees are included in the analysis. The selected regional airports are; Abilene Regional Airport (ABI), East Texas Regional Airport (GGG), San Angelo Regional Airport (SJT), Tyler Pounds Regional Airport (TYR), Waco Regional Airport (ACT) and Wichita Falls Municipal Airport (SPS). The proposed "short-haul" scheduled flights from these airports to DFW are enumerated for cost evaluation and sustainability. Eight different turboprop aircraft with 6 to 80 seats are considered in this study and the results prove that this "short-haul" air service is feasible and a profitable venture to operate as a no frills, Low Cost Air Carrier Service (LCAC).

McMurdo Station, a research and support facility operated by the National Science Foundation, is located on Ross Island, immediately adjacent to mainland Antarctica. The station requires aircraft to move people and cargo between Christchurch, New Zealand, and McMurdo Station during the normal operating season of early September through late February. In addition, aircraft deliver people and cargo to the South Pole Station and field camps throughout the continent. Historically, air service has been primarily provided by US military aircraft using three different runway surfaces (sea ice, snow, and glacial ice) at 3 different geographic locations on the frozen Ross Sea or the adjacent Ross Ice Shelf. In 2011, an effort was undertaken to develop an airfield master plan for consolidating all aircraft operations into one location. The master planning effort included several major components to be optimized: runway and skiway headings, aircraft parking aprons, refueling point aprons, supporting town site location, navigational aids (NAVAIDs), and air traffic control tower. Although these components are part of most traditional airfield master plans, the unusual location and environmental factors made the development process unique and challenging, such as snow drifting, storm wind vs. prevailing wind operations, and snow contamination from aircraft engine soot. After extensive coordination and reviews with stakeholders, a recommended optimized airfield master plan layout was created for operating a single airfield complex at McMurdo Station, Antarctica. The surface area to be groomed was reduced approximately 8% as compared to the existing layout while providing more capability.

Based on the case studies in California, this paper investigates how the operations of the legacy airlines and LCCs impact the development of secondary airports. The objective is to identify the key factors driving the dynamics of airport selection by airlines - especially the LCCs - and use this information to identify policies and measures that planners can use to guide the development of secondary airports. We also investigate the smaller airports that are too far from the major metropolitan areas to be attractive to LCCs and examine their options for growing and sustaining traffic. Based on a review of literature and interviews with public officials at selected airports in California, we make recommendations for steps the secondary and small airports should be taking to improve and sustain airline traffic.

A Construction Safety and Phasing Plan (CSPP) is a necessary document for any airport construction project that could have an impact on normal airport operations. The basic intent of every CSPP is to minimize risk and maintain safe airport operations while construction activities proceed. However, the requirements for such documents vary significantly around the world. Currently there is no readily available source of information that identifies the differences in CSPP requirements between ICAO contracting States. This can pose a challenge for consultancies and engineering firms breaking away from domestic markets or participating in overseas projects for the first time. Consequently it may be a challenge for many firms to implement a best practice approach to CSPP development where there is very little documentation of what is best practice. In this regard, this paper will present research that identifies some of the key differences that exist in the published requirements and practical development of airport CSPPs throughout many ICAO States. The paper will also identify, at the fundamental level, what can be argued as the existing industry best practice for CSPP development. This will be supported by empirical research and guiding principles found in project management research and the study of human factors. This paper will conclude with an identification of best practices for CSPP development and put forth recommendations concerning future CSPP regulation.

While many agencies responsible for the management of airport infrastructure are working towards holistic infrastructure management, there is currently no standard in place in Canada and the United States. An international standards organization 55000 series of standards is currently under development. This standard uses the British Standards Institute Publicly Available Specification PAS 55 as a foundation for the standard development which is due for completion in late 2013. In 2011, the Transportation Research Board (TRB) Airport Cooperative Research Program (ACRP), sponsored a study to develop a guidebook and primer for airport asset managers in Canada and the United States. This paper, outlines the results of asset management best appropriate practices gleaned from surveys and interviews of over 50 airports of various sizes across North America. The paper outlines a 10 step process for successful asset management implementation and provides details on policy, objectives, strategies and plans for implementing an asset management framework. Specific best practices are described and highlighted along with the keys to their successful implementation.

Funding projects to improve the intermodal connectivity between the surface transportation system and airports is often complicated by the need to draw on a range of different funding programs and sources, each with their own project eligibility requirements and regulations. This paper presents the findings of two case studies of the funding for two intermodal airport ground access projects in the United States, one of which was recently completed while the other is currently under construction. The first case study examines the funding strategy developed for the Miami Intermodal Center, a major intermodal facility adjacent to Miami International Airport that includes a consolidated rental car center, parking, a station for regional and long-distance trains, an extension of the Miami Metro to the rail station, a bus station, and an automated people-mover link between the facility and the airport. The second case study examines the funding plan for the development of a 3.2-mile automated people-mover link from the Coliseum/Oakland Airport station of the Bay Area Rapid Transit system to Oakland International Airport.

In September 2012, the Federal Aviation Administration (FAA) released an updated version of the Airport Design Circular, AC 150/5300-13, Airport Design. This circular introduced several new standards and recommendations for the geometric layout of runway and taxiway intersections at civilian airports. While designing a taxiway reconstruction project at Lambert-St. Louis International Airport, which included a runway-taxiway intersection, multiple taxiway-taxiway intersections and a high-speed runway exit taxiway, the updated airport geometry standards yielded many challenges. These challenges included how to effectively and efficiently reconfigure taxiway intersection pavement geometry while connecting to existing pavement, the placement of new taxiway edge lighting at fillets, tapers and intersections of both, and positioning of new pavement markings to include the enhanced taxiway centerlines, taxiway shoulder markings, surface painted runway hold signs and hold lines. These challenges necessitated an analysis and unique approach to each of the different taxiway intersections within this project. This paper will provide a brief overview of the new airport design standards, the current airfield lighting and marking guidelines, and outline the criteria differences that arose when using all three guidelines documents in design. Finally, this paper will detail the approach used to overcome these challenges during the design of the Reconstruction Taxiway Delta and Echo and Removal of Taxiway November Project at Lambert-St Louis International Airport.