Safety benefits of right-turn lanes (RTLs) have typically been estimated on the premise that right-turn movements (RTMs) only lead to rear-end (RE) crashes, and RTLs completely eliminate such RE crashes. This premise is reexamined in this study. Five-year, event-specific, statewide, historical data of traffic crashes reported on Minnesota’s two-lane trunk highways were analyzed using logistic regression models (LRMs) to determine the safety impacts of RTMs/RTLs at uncontrolled major road approaches to intersections/driveways. It was found that the crashes caused by right-turning vehicles were less severe (mostly property damage), and interestingly, only 39% of those were identified as RE type. Right-turn lanes were found to reduce such RE crashes, on average, by 30% (not completely eliminate), reduce crash injury severity, and decrease the associated economic costs by 26%. Relative risks of RE crashes at driveways were 1.3 to 1.9 times higher compared with those at intersections, suggesting the need for separate set of volume warrants for RTLs. Logistic regression models developed provide the relationships to quantify RTL benefits for different roadway/operating conditions found statewide and can serve as a basis for safety-based warrants.

Deer-vehicle crashes are a growing problem in Iowa where deer-vehicle crashes represent 13% of all crashes reported. In 2009, these crashes resulted in nine fatalities and 451 injuries in the state. Deer-vehicle crashes are a problem even in urban areas of Iowa. It is known that deer-vehicle crashes are typically underreported. To address this underreporting, deer carcass salvage reports may be used to augment deer-vehicle crash reports. The objective of this paper is to exploit two sources of deer-vehicle crash data using a statistically reliable assessment methodology, empirical Bayes, to assess the potential for safety improvement of 150 urban highway sections in Iowa. Reconciliation of records to reduce double counting is discussed and a negative binomial regression model of deer-vehicle crash frequency as a function of roadway and environmental factors is estimated. The 25 most promising segments for deer-vehicle crash countermeasures are identified, mostly located on high-speed roadways, roadway segments with gravel right shoulders, and segments adjacent to grasslands. The methodology facilitates the identification of locations for countermeasure implementation as well as monitoring deer-vehicle crash trends.

The concept of freight consolidation center (FCC) has emerged in recent years. Although several case studies have indicated that FCCs are beneficial to the operation of urban transportation systems, the implementation of this concept has proven difficult because the construction and operation of a FCC involves the coordination of different, and conflicting, stakeholders. Unlike other traditional approaches, this paper investigates the FCC development issue using experimental economics. First, profit functions are defined for involved stakeholders; based on those profit functions, four players—carriers, operators, government, and residents—bid on rent, financial incentives, and wages to maximize their own profits. Eight scenarios are analyzed and compared to determine potential influential factors and appropriate conditions for FCC decision making. Results show that public–private partnership lowers rent and increases wages, which leads to higher carrier, operator, and resident profits. A central location lowers rent, wages, financial incentives, and all stakeholders’ profits. A larger carrier size benefits all stakeholders. In conclusion, the appropriate conditions for FCC development are public–private partnerships in noncentral locations with large carrier sizes.

A method is developed to estimate the mean texture depth (MTD) value, which to some extent represents pavement quality, using measurements from a microphone mounted underneath a moving vehicle. Such measurements will include tire-generated sound that carries information about the road macrotexture as well as noise generated by the wind and vehicle. The proposed method uses principal component analysis (PCA) to differentiate important information about the road surface from noisy data while the vehicle is moving. The variations in frequency of the noise are assumed to be small compared with the variations in frequency of the signal related to the road-surface condition, which allows the PCA approach to separate noise from signals that carry information about the road-surface condition. The analysis begins with acoustic pressure measurements being made over various road-surface conditions underneath a moving vehicle. Fourier transforms are taken over various time windows and a PCA is performed over the resulting vectors. This yields a set of PC vectors representing the road-surface conditions. The frequency range of concern is from 0 to 2,000 Hz, according to the amplitude of frequency spectra of collected acoustic measurement. The pavement-macrotexture depth (i.e., MTD) is estimated by matching the PC vector set derived from unknown road conditions with one of the vector sets of known road conditions. Successful applications of this method are demonstrated by accurate estimations of the MTD of pavement directly from acoustic measurements. The results indicate that PCA is a powerful approach to eliminate the noise that is not associated with the road surface, and therefore, the PC vectors can be used to accurately match the MTD values. The PCA approach for tire-generated sound might also be used to differentiate subsurface road conditions, a precursor of many defects such as potholes and severe cracking.

In an effort to minimize the risk of overdesign or underdesign of pavement structures in the Mechanistic-Empirical Pavement Design Guide (MEPDG) in Alabama, sensitivity analysis was utilized to examine the potential for implementation of various levels of traffic inputs. Changes in required pavement thickness as a result of differences between nationwide, statewide, regional, and site-specific traffic factors were used as sensitivity indicators. The effects of traffic inputs on pavement design were deemed to be practically significant when the thickness needed to maintain an acceptable level of pavement performance changed 1.3 cm (0.5 in.) or more from the baseline thickness developed from statewide traffic inputs. This paper presents the sensitivity analysis results for nationwide traffic inputs and direction-specific inputs when the effects of each were compared with the effect of statewide inputs on pavement thickness. Recommendations include the use of a procedure that incorporates required pavement thickness when determining an appropriate level of traffic inputs. Based on the results of the sensitivity analysis, statewide inputs are preferred over the default nationwide values; however, when the impacts of direction-specific inputs on pavement thickness exceed sensitivity criteria, statewide traffic inputs are not sufficient and direction-specific inputs or cluster-averaged inputs are recommended.

Facing pavement preservation challenges as a result of funding shortages, the Georgia Department of Transportation (GDOT) has developed an innovative micromilling resurfacing method to cost-effectively preserve its pavements. The cost saving is significant: approximately $60,000 per lane mile. To ensure that a smooth micromilled surface texture provides a good bond and water runoff capability, which is the key in this new method, a new, stringent ridge-to-valley-depth (RVD) specification has been established for quantitatively evaluating micromilled surface quality. This paper explores the possibility of using emerging three-dimensional (3D) line laser imaging technology to develop a full-lane quality control method that can measure RVD, provide quality control covering a full lane, and identify problem areas. A lab test was first conducted to critically assess the accuracy of the proposed method by using an artifact: a wood panel with V-shaped grooves of a known depth to simulate the ridges and valleys on a micromilled surface. Results show that the proposed method is very promising and can measure RVD with an error of less than 0.4 mm (0.016 in.). A field test was conducted by using Georgia Tech’s sensing vehicle to collect 3D range data at two 0.8-km (0.5-mi) segments on a micromilling resurfacing project on I-95. Results show that the RVDs in the transverse direction can effectively and quantitatively differentiate between smooth (mean $\mathrm{RVD}=2.9\mathrm{mm}$; 0.114 in.) and rough (mean $\mathrm{RVD}=4.8\mathrm{mm}$; 0.189 in.) micromilled surface textures. A case study shows that other problem areas on the micromilled surface, such as underlying cracks and isolated rough spots that will lead to premature failure, can also be identified by using the proposed method, so proper pretreatment methods (e.g., deep patches or crack sealing) can be effectively applied before resurfacing to ensure the longevity of the pavement. At the end of the paper, conclusions are made and recommendations are discussed for future research.

This study presents the findings from research conducted at the University of New Hampshire Stormwater Center (UNHSC) which investigated porous pavements as a potential strategy for minimizing the use of deicing chemicals for winter maintenance. In cold regions, chloride is an integral component of winter maintenance and safe usage of transportation surfaces. Chloride-laden runoff from impervious surfaces threatens aquatic habitats, degrades drinking water supplies, and corrodes infrastructure. State and federal environmental agencies are beginning to regulate chloride usage through the implementation of total maximum daily loads (TMDLs). Parking surfaces in some watershed studies have been shown to be the single largest chloride source in storm-water runoff, in some instances contributing up to 50% of the total load. This study examined winter maintenance over two winters and 38 storms from 2006–2008. The study evaluated winter performance in response to deicing practices by measuring skid resistance, the degree of snow and ice cover, recoverable chloride mass, and effective salt loads. During and just after snowstorms, analysis of snow/ice cover and pavement skid resistance demonstrated that from 64 to 77% less salt was needed in order for a porous asphalt (PA) lot to maintain equivalent or better surface conditions as compared to a reference dense-mix asphalt (DMA) lot. Between snow storms, the lack of standing water on porous asphalt greatly reduced the frequency and mass of salt applications needed to control black ice. Although the DMA lot received a typical salt application that was four times greater, the annual median snow and ice surface cover for the PA lot was not significantly different ($p=0.749$, 95% confidence), and the annual median weighted skid resistance for the PA lot was 12% greater ($p=0.061$, 95% confidence). A companion study on the hydrologic and water quality performance reported that freeze-thaw was limited due to the well-drained nature designed into the system, and surface infiltration capacities remained in excess of $500\mathrm{cm}/\mathrm{h}$ ($200\mathrm{in.}/\mathrm{h}$), despite the fact that the maximum frost penetration depth observed was nearly 71 cm (28 in.). Porous pavements present one viable potential strategy for chloride reduction.

Concrete block pavements (CBP) are increasingly used in pedestrian roads and low-volume highways. Concrete block pavements experience various failure modes, including shifting, cracking, spalling, and erosion of jointing sand. One of the most important causes of failure is the interlocking with high force between weak blocks. Laying patterns affect the global and local behaviors of different block types. A simple and efficient testing program was introduced and conducted for evaluating the interlocking performance of complex block shapes and different block patterns under horizontal loading conditions. An image technique, video capturing and block movement plots, was also applied to consider the individual movement of laid blocks on a test setup. A displacement-moment (D-moment) concept was suggested to interpret the local and global behavior of different block types and patterns. Typical rectangular and shaped block types with three different laying patterns such as stretcher, basket weave, and herringbone were compared in executed experimental results and interpreted parameters, i.e., maximum force, energy, and D-moment.

Rail seat deterioration (RSD) continues to be identified as one of the primary factors limiting concrete crosstie service life in North America. RSD refers to the degradation of material at the contact interface between the concrete crosstie rail seat and the rail pad that protects the bearing area of the crosstie. Industry experts consider abrasion to be a viable mechanism leading to RSD. A lack of understanding of the complex interactions affecting the severity of abrasion has resulted in an empirical design process for concrete crossties and fastening systems. The objective of this study is to quantify the abrasion resistance of concrete rail seats by using a variety of concrete mix designs and other materials relevant to the rail industry. To simulate the abrasion mechanism of RSD, a small-scale test for abrasion resistance (SSTAR) was designed by researchers at the University of Illinois at Urbana-Champaign (UIUC). Data obtained from the SSTAR will help the rail industry mechanistically design concrete crossties by improving the current understanding of the performance of various concrete abrasion mitigation approaches. Preliminary results show that abrasion mitigation approaches such as the addition of metallic fine aggregates (MFA), steel fibers, and the application of coatings improve the abrasion resistance of concrete specimens.

Access management in transportation planning can reduce crashes, increase route capacities, and reduce travel times. The literature suggests a need for performance metrics and a decision-aiding framework to guide access management programs across large corridor networks and diverse time horizons. This paper describes a quantitative framework to support access management programs that focus on safety, applying multicriteria analysis, and cost-benefit analysis with parameter uncertainties. The metrics used to assess relative needs at existing access points include crash exposure, crash intensity, traffic exposure, and costs of typical access management activities. Uncertain parameters that influence the estimates of the potential benefits and costs are identified and treated via a numerical interval analysis. The framework is demonstrated at several geographic scales and locations including 7,000 km of highways of a $\mathrm{110,000}\text{-}{\mathrm{km}}^2$ region and its several subregions. The results assist decision makers to prioritize which route segments should be addressed sooner and investigated further by elicitation and collection of additional data, reserving right of way, closing access points, planning new alignments, facilitating developer proffers, etc. This approach that combines multicriteria analysis with cost-benefit analysis is transferable to other topics involving transportation engineering and resource allocation.

Daily congestion on transportation networks is the one of the biggest problems that city authorities face. Different strategies for transportation-demand management have been developed with the aim to decrease existing negative traffic impacts. Available strategies are based on the use of accessible transportation infrastructure and have their own characteristics. In accordance with these specific characteristics, each strategy is more or less suitable for a particular transportation network. In this paper, the writers develop a model for the best strategy selection from transportation and drivers’ point-of-view. The model is based on the analytical network process, i.e., on the combination with the benefits, opportunities, costs, and risks (BOCR) merit approach, with consideration of BOCR. The approach addresses problems regarding the network structure, whereby the various criteria are relevant for the considered problem. The proposed model is applied and tested on real data collected in Belgrade, Serbia.

This paper points out questionable derivations for the formulated solution in the algebraic approach for the optimal length of local bus route of a traffic model for bus service zones. It also provides revisions for the algebraic approach to prove the existence and uniqueness for the formulated optimal solution. An iterative method was then applied to obtain an alternative sequence that converges to the optimal solution. The same numerical examples in the literature are examined to support the findings.