Current design practices in North America are based mainly on 2D analysis of the highway alignment and do not account for the operating speed adopted by drivers. A more accurate approach should consider the interaction among the horizontal alignment, vertical alignment, and cross section based on the predicted operating speed. By combining the operating speed models along with 3D sight distance and vehicle dynamics models, a practical application of this approach is presented using an 8-km segment of Highway 61 (Ontario, Canada). By comparing the profile of predicted operating speed to the profile of allowable speed, based on 3D sight distance and vehicle dynamics, the consistency or deficiency in the highway segment is identified. The paper demonstrates the applicability of the 3D models to real highway segments and their usefulness in evaluating the adequacy of new designs or roads already in service. As the difference between the 2D and 3D results is significant, the 2D analysis is proven to be inadequate for such an evaluation, and the need for a 3D analysis is evident. Also, field measurements show that the accuracy of operating speed models is considerably compromised on combined horizontal and vertical curves. Thus, the results indicate the need to develop operating speed models that account for the effect of combined alignments and nighttime driving.

Twenty-two different signal displays for permitted and protected left turns were evaluated from a driver comprehension perspective. The objective was to identify which alternate signal displays used to convey the same left-turn message to the driver are better comprehended and therefore recommended for use in the field. Protected displays compliant with the Manual on Uniform Traffic Control Devices were found to be better comprehended than certain noncompliant displays; however, some noncompliant permitted displays were found to outperform their compliant counterparts. Regional comprehension biases are nonexistent for the most part, regardless of display compliance with the Manual on Uniform Traffic Control Devices. Permitted left-turn signals using indications other than a steady green ball were found to enhance driver comprehension. The “Left Turn Must Yield on Green Ball” sign used with a “doghouse” display is beneficial during the permitted phase, but confusing when displayed during the protected left-and-through phase. Other supplemental signs used with various left-turn displays were also evaluated.

Advanced technologies under the aegis of advanced traveler information systems and advanced traffic management systems are being employed to address the debilitating traffic congestion problem. Broadly identified under the label intelligent transportation systems (ITS), they focus on enhancing the efficiency of the existing roadway utilization. Though ITS has transitioned from the conceptual framework stage to the operational test phase that analyzes real-world feasibility, studies that systematically quantify the multidimensional real-world impacts of these technologies in terms of mobility, safety, and air quality, are lacking. This paper proposes a simulation-based framework to address the mobility impacts of these technologies through the provision of information to travelers. The information provision technologies are labeled as advanced information systems (AIS), and include pretrip information, en route information, variable message signs, and combinations thereof. The primary focus of the paper is to evaluate alternative AIS technologies using the heavily traveled Borman Expressway corridor in northwestern Indiana as a case study. Simulation results provide insights into the mobility impacts of AIS technologies, and contrast the effectiveness of alternative information provision sources and strategies.

This study attempts to examine driver comprehension of the traffic information that is presented in three formats, namely, the numerical format, the description format, and the switch-on-light format. A stated preference survey with well designed attributes regarding travel conditions and comprising a total of 475 successful cases for Hong Kong drivers has been conducted for this purpose. Binary logit models with respect to drivers' traveling preference of two designated routes under different traffic conditions were developed and found to have considerably high goodness-of-fit statistical values. The final models were specified with 11 variables. The explanatory variables employed in the models include those referring to respondents' socioeconomic background and those characterizing the transport network. Based on the findings, it is possible to conclude that drivers have different comprehension of the formats for presenting traffic information on variable message signs, and the message formats can induce biases toward a route in drivers' decision-making processes.

This paper presents a computer model, named WNDROS, for optimizing the runway orientation based on given wind data and allowable crosswind component. The model is based on a mathematical formulation, which transfers circles and radial lines of the wind rose method into points with numeric coordinates. The development of the model is presented and discussed in detail in this paper. In determining the wind coverage for a given runway direction, the model calculates exactly the areas of sectors covered, fully or partially, by the runway template and determines a factor for adjusting the wind data of covered sectors. The optimization is achieved through an “exhaustive search” by evaluating the coverage at small increments of orientation angle covering all possible directions. The model compares the results of evaluated coverage and reports the best solution together with several competitive alternatives. Results of the model were thoroughly verified against exact measurements in AutoCAD, which confirmed the model accuracy. The model has a flexibility to function under any combination of number of wind directions, number of wind speed intervals, and allowable crosswind. The model is demonstrated through a numerical example and proves to be convenient and accurate.

The dynamic response of a pavement structure, subject to a moving vehicle load, is investigated on a unified analytic framework. The time-dependent deflection and its derived dynamic quantities for a slab structure are obtained by linking together the characteristics of a road profile, a moving vehicle, and a slab on a viscoelastic foundation. Examples are presented to illustrate the analytic results derived from the established framework. The model may be applied to understand quantitatively the dynamic deflection and dynamic strains within a rigid pavement structure. It is found that the surface roughness effect on the dynamic response of a slab structure plays an important role for the serviceable life span of a pavement structure and may be taken into account in pavement design. The model may be calibrated to estimate the k-value for the evaluation of the subgrade support to a pavement as it ages.

The International Friction Index (IFI) is used for consideration of skid resistance and macrotexture in a probabilistic pavement performance modeling framework. IFI provides a friction scale that can be used for comparisons at international level and consists of skid resistance and macrotexture values, as macrotexture influences the variation of skid resistance by speed. Threshold values are established to define high quality and low quality conditions of skid resistance and macrotexture that are combined to assess the adequacy of pavement friction (IFI) for scheduling of maintenance activities. The methodology consists of three steps: (1) Use the local device-specific thresholds on friction and macrotexture to obtain IFI threshold values; (2) determine a fixed IFI threshold value; and (3) obtain modified device-specific threshold values based on the fixed IFI. Data for the present analysis have been collected on the Hungarian asphalt-concrete motorway system between 1994 and 1997. The condition states based on the modified device-specific threshold values are used to establish a Markov chain model that is in good correlation with the actual performance data.

This paper describes a total quality approach to the specification of pavements surfaced with pavers, which allows those factors that govern the performance of a pavement to be identified and quantified. Case studies are presented for seven projects that have underperformed and for two projects that have performed well. These case studies are used to define those factors that commonly lead to failure. In addition to the usual technical inputs to the specification procedure, the total quality method also includes an appraisal of any unusual environmental conditions that might prevail. It also takes into account the public profile of the project and how visible the project is to the general public. By integrating these “soft” factors with the traditionally applied technical issues, the paper shows how a pavement can be guaranteed to perform to the client's requirements. A total quality chart is presented that guides its user toward appropriate specifications of all of the critical elements in a pavement.

The lack of an effective bridge deck condition assessment tool prompted a collaborative research program between Dalhousie University DalTech and the Nova Scotia Department of Transportation and Public Works to assess the accuracy and variability of ground-penetrating radar (GPR) for asphalt-covered, reinforced-concrete bridge deck deterioration estimates. The quantity and location of GPR-predicted deterioration on nine bridge decks was compared to actual deterioration detected using the half-cell potential and chain drag survey methods. Good spatial correlation and excellent quantitative correlation were observed between the GPR predictions and the actual deterioration found on the nine decks. These findings have demonstrated that GPR can provide management with a valuable tool for estimating deck repair quantities and prioritization of potential repair candidates on a network level.

This paper examines the aerodynamic characteristics of a freight pipeline system in which freight capsules are individually propelled by electrical motors. The fundamental difference between this system and the more extensively studied pneumatic capsule pipeline is the different role played by aerodynamic forces. In a driven system the propelled capsules are resisted by aerodynamic forces and, in reaction, pump air through the tube. In contrast, in a pneumatically propelled system external blowers pump air through the tubes, and this provides the thrust for the capsules. An incompressible transient analysis is developed to study the aerodynamics of multiple capsules in a cross-linked two-bore pipeline. An aerodynamic friction coefficient is used as a cost parameter to compare the effects of capsule blockage and headway and to assess the merits of adits and vents. We conclude that optimum efficiency for off-design operation is obtained with long platoons of capsules in vented or adit connected tubes.

This paper describes a full-scale field trial carried out on plastic pipes buried in trenches, which were repeatedly loaded by a heavy vehicle driven along an overlying haul road. The vertical deformation of the pipes was recorded throughout the test for up to 1,000 loading passes and was observed to increase rapidly during the initial loading cycles with the rate of deformation reducing markedly as further cycles of loading were applied. This indicated that the pipe/soil system became more stable by repeated stress application. Power-law curves were developed from the recorded field data and were used to predict the long-term pipe deformation from initial loading cycles. The curves showed good correlation, and the predicted values agreed closely with measured values. The two types of surround material (nominally compacted sand and gravel) were found to have little effect on the rate of accumulation of deformation.

Cost data and bridge property data were collected for 121 timber bridges constructed as demonstration projects and for 206 timber bridges that were not demonstration projects. After controlling for selected structural and regional independent variables, demonstration bridge superstructures were approximately $120 per square meter more expensive than nondemonstration bridge superstructures.