Time filter

Source Type

Bend, OR, United States

Cregger J.,Transportation Group
2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings | Year: 2015

Although U.S. policies encourage adoption of plug-in electric vehicles (PEVs), they make up a small share (less than one percent) of U.S. vehicle sales. There are many challenges to increasing PEV market share-one of which is the lack of public charging infrastructure, which may reduce consumer acceptance and confidence in PEVs. This paper highlights issues surrounding new charging infrastructure, documents existing infrastructure, and discusses the role of policy in supporting installation of new infrastructure. Eight states have set a goal of having 3.3 million registered Zero Emissions Vehicles (ZEVs)-most of which will be PEVs-in operation by 2025; this target is used to estimate the cost of expanding infrastructure in those states over the next decade. © 2015 IEEE.

Hellinga B.,University of Waterloo | Mandelzys M.,Transportation Group
Journal of Transportation Engineering | Year: 2011

Variable speed limit (VSL) systems enable freeway system managers to change the posted speed limit on a section of roadway in response to varying conditions. VSL system goals may include homogenizing traffic flow, improving safety, and/or reducing driver stress. Although it is understood that the effectiveness of VSL systems is impacted by the level of driver compliance, which itself is influenced by the extent of speed limit enforcement, very little is known about the strength of these impacts. This paper uses a simulation model to evaluate the sensitivity of the safety and operational impacts of VSL to driver compliance. Several scenarios for driver compliance were modeled using the PARAMICS microscopic traffic simulator. Findings indicated that VSL impacts are very sensitive to the level of driver compliance. Safety was shown to be positively correlated with the level of compliance, and travel time was shown to be negatively correlated. However, it was also found that the magnitude of the impact is strongly influenced by the VSL control strategy (i.e., set of rules for incrementing and decrementing the speed limits) being used. Therefore, selection of the VSL control strategy cannot be done independently of the decision regarding speed limit enforcement. © 2011 American Society of Civil Engineers.

Gharabegian A.,Transportation Group
INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | Year: 2015

When it is completed, the California High-Speed Rail Corridor will connect San Francisco to Anaheim. California High-Speed Rail Authority is in process of preparing Environmental Impact Statements (EIS) for different segments of the project in accordance to the Federal Railroad Administration (FRA) guidelines. Potential noise and vibration impacts due to the proposed project were evaluated using the FRA procedures as they were modified for the project as well as measured noise and vibration data. Impacts were predicted at sensitive locations such as residences, schools, hotels, and commercial facilities located along the corridor for several different alignments and different options which included tracks being at grade, elevated, or in trench. Parts of the alignment are traveling through the heavily developed urban areas and other parts through rural areas with scattered receptors. © 2015 by ASME.

Hu K.,Transportation Group
Bridge Construction | Year: 2015

By applying the new type of the isodirectionally turning stay cable system to cable-stayed bridge, the stay cables at the pylon of the bridge can be anchored with no tensile stress in point of mechanism. To solve the problem of locating the isodirectionally turning stay cables and to make the techniques related to the stay cables more practical, a reference cylinder locating method for the stay cables was put forward. The stay cables were assumed to turn around a virtual cylinder that had the same axle with that of the pylon and the perpendicularity plane of the stay cables was assumed to touch the cylinder, a vertical tangent line of fixed location was hence formed and the tangent line could contribute the reference for computing the locating of the stay cables. The given design conditions of the bridge were taken as the major control parameters and control target. In accordance with the structural design characteristics, the undetermined parameters that were closely associated with the major control parameters were selected and controlled, the control sequence was set and the geometric and mechanical relations among the parameters were established. By repeated computation, the coincidence of the computation with the control target was achieved and the problem of locating the stay cables was accordingly systematically solved. The reference cylinder locating method and locating process were compiled as a locating computation modulus, were built into the stay cable design program and applied to the Second Wuhu Changjiang River Bridge. The results of the application demonstrated that the method and process could achieve the ideal locating of the isodirectionally turning stay cables. ©, 2015, Wuhan Bridge Research Institute. All right reserved.

Chu Y.-L.,Transportation Group
Transportation Research Record | Year: 2011

This paper presents the development of a combined equilibrium model for the simultaneous prediction of the destination and route choices that face suburban or rural automobile travelers. Destination choice is given by a dogit model to take into account the travel behavior of compulsory (work) and discretionary (nonwork) trips. A logit-based route-choice model was employed, with a stochastic user equilibrium principle, to develop route flows between each origin-destination pair. The natural logarithm of the denominator of the logit route-choice model (i.e., log-sum) was computed and fed back into the destination-choice step. Under this iterative process, the destination choice for discretionary trips responded to changing travel-cost conditions, whereas the destination choice for compulsory trips remained fixed in the study time period. The proposed combined destination- and route-choice (CDR) model can itself be reformulated as an equivalent convex programming problem with linear constraints, a great advantage from a computational perspective. The CDR model was applied empirically to a county-level network in New Jersey. The results encourage further applications of the CDR model to large-scale networks.

Discover hidden collaborations