Search

Pavement grooving is an accepted remedial measure to improve skid resistance and reduce crash rates on horizontal curves. However, besides experience-based guidelines, currently no mechanistic procedure is available for quantitative evaluation of the effectiveness of a pavement grooving design in skidding prevention on horizontal curves. To ensure driving safety on wet horizontal curves in particular, there is a practical need for a reliable procedure to determine the effectiveness of a pavement grooving design in increasing tire–pavement skid resistance and the maximum safe driving speed. With the aim to bridge the knowledge gap, this paper presents a computer simulation procedure based on the finite-element method to evaluate the effectiveness of a pavement grooving design in terms of its ability to increase the maximum safe vehicle speed and reduce skidding potential on a wet horizontal curve. For illustration, three common grooving designs were considered, each having a different groove width, depth, and spacing. For each grooving design, two orientations of grooving, namely longitudinal and transverse grooves, were studied. The simulation model allowed different operating conditions to be analyzed, including different geometric dimensions of a horizontal curve, pavement surface properties, and pavement surface water film thicknesses. The analysis not only confirmed past observations and measurements that longitudinal grooving was significantly more effective than transverse grooving in raising pavement skid resistance and the maximum safe driving speed on horizontal curves, but also quantitatively provided their respective magnitudes of improvement. [ABSTRACT FROM AUTHOR]

Connected and automated vehicle (CAV) exclusive lanes are an important application of intelligent transportation technologies on highways. However, current research on CAVexclusive lanes mainly focuses on basic road segments rather than on on-ramp junctions. This paper analyzed the impact of CAV exclusive lanes on the traffic capacity of on-ramp junctions through theoretical analysis and numerical simulation. This paper established a capacity model for heterogeneous traffic consisting of CAVs and manual vehicles (MVs) considering the CAV degradation mechanism. Three key parameters, namely the CAV penetration rate, the proportion of CAVs on regular lanes, and a CAV platoon coefficient, were introduced into the heterogeneous traffic capacity model. Based on this input, the relationship between traffic capacity and the three parameters was analyzed on regular lanes. The critical CAV penetration rate at which a CAV exclusive lane reaches saturation was expressed mathematically. An on-ramp junction scenario with a CAV exclusive lane was simulated numerically with microscopic heterogeneous traffic flow models. Experimental results showed that congestion at the junction area no longer spread upstream after the CAV penetration rate exceeded 70% without CAVexclusive lanes. However, for the case in which a CAVexclusive lane was used, CAVs on the exclusive lane traveled quickly through the junction and effectively relieved traffic congestion when the CAV penetration rate reached 40%. The results also showed that a long acceleration lane slightly reduced the CAV platoon coefficient. In addition, a CAVexclusive lane improved traffic capacity when the CAV penetration rate was higher than 30%, regardless of the length of the acceleration lane. [ABSTRACT FROM AUTHOR]

There is an urgent need for policies to close the existing financing gap for civil infrastructure. However, identification of the desired scenarios for the closure of the financing gap is complex because there are many factors that affect investment in infrastructure. Thus, comprehensive models are required to (1) simulate the impacts of policies, and (2) identify the highly likely scenarios for desired policy outcomes. The objective of this paper is to create a simulation model for ex-ante analysis of financing policies in highway transportation infrastructure in the United States. Using the agent-based technique, this model simulates the microbehaviors of state Departments of Transportation, private institutional investors, and the public. Using the output of the simulation model, financing landscapes of the U.S. transportation infrastructure are developed. The simulated landscape is shown to be helpful in identifying the highly likely scenarios leading to a high level of investment in highway transportation infrastructure under the existing infrastructure investment structures and budget constraints in the United States. The study presented in this paper is novel with respect to (1) the application of the system-of-systems modeling in the analysis of transportation infrastructure financing policies, (2) identification of the desired policy scenarios and their likelihoods for closure of the financing gap in the presence of uncertainties and adaptive behaviors, and (3) simulation and visualization of the impacts of financing policies at the state and national levels. The model promotes a data-driven policy analysis and provides policymakers with a tool to simultaneously account for the impacts of several factors and uncertainties. [ABSTRACT FROM AUTHOR]

Trucks move around 70% of the freight weight in the United States. The combination of increased commercial motor vehicle traffic, tighter delivery schedules, and federally regulated limits on driving time lead to a nationally recognized problem on interstate highways in the United States, i.e., increased demand for commercial truck parking. Unavailability of sufficient parking spaces at rest areas results in illegal and unsafe parking at entrance/exit ramps, and other unauthorized areas. The research reported in this paper, funded by the Florida DOT, sought to understand the truck parking problem in Florida, determine the supply and demand characteristics for commercial truck parking, assess technology that can be used to improve parking management, and conduct a pilot project to test a smart truck parkingmanagement technology to make better utilization of commercial parking spaces at public rest areas. [ABSTRACT FROM AUTHOR]

Istanbul, the only city that straddles two continents, Europe and Asia, is one of the biggest metropolitan areas in the world with over thirteen million residents. The demand for transportation in Istanbul has been boosted considerably due to the increasing population and rising vehicle ownership. On the other hand, the transportation infrastructure has not been developing sufficiently to meet this demand. Hence, the Turkish government and local authorities sought various alternatives to the road transportation system in Istanbul and came up with the Marmaray Project, which was planned and designed to serve both intraurban and interurban passengers and freight transport. One of the main aims of the Marmaray Project is to shift the traffic demand from roads to the rail network. In this paper, a travel demand modeling framework was developed to calculate the transportation demand of the Marmaray corridor. In addition, a model including empirical modeling methods was developed for the highways to estimate the origin and destination matrices. The developed model was used to estimate freight and passenger transportation between Istanbul and other Turkish provinces. The estimated transportation demand results were used to calculate the required train numbers on a daily basis through the Marmaray corridor and some suggestions were put forward to increase the capacity of this corridor. [ABSTRACT FROM AUTHOR]