A mechanism is unveiled by which congestion forms and persists near the base of an uphill expressway segment, causing significant reductions in output flow. The traffic condition in the expressway's shoulder lane is key to the mechanism. When shoulder-lane flow was low, drivers maneuvered around...

The paper explores how the coordination of vehicle schedules in a public transit system affects generalized costs. We consider an idealized system that delivers its users to a common destination by requiring each to transfer from a feeder- to a trunk-line vehicle. Continuum models are used first...

The maximal rates that buses can discharge from bus stops are examined. Models were developed to estimate these capacities for curbside stops that are isolated from the effects of traffic signals. The estimates account for key features of the stops, including their target service levels assigned...

In this paper we use a case study approach to examine how airport operators are addressing bicycle access to their properties and the motivations and obstacles they face, in light of new policies to integrate bicycles, along with transit and walking, into transportation planning, design and...

In the face of increasing sprawl and car-dependence in US metropolitan areas, young people – especially teens in middle-class suburbs – may be experiencing new mobilities generated by their near-universal adoption of cell phones and increasing access to private automobiles. The...

Traffic collisions are a leading cause of death and injury in California and the number one cause of death for people between the ages of one and 44. High-visibility enforcement programs (HVEs) are administered nationwide by the National Highway Traffic Safety Administration, and combine...

Similarly to the US, driving a car to work continues to gain ground in Ireland and the country is presented with major challenges in environment and health as a consequence. In safety, at least, Ireland has had some major successes. In 40 years, the number of fatalities has fallen from 640 to...

From a recent study of safety evaluation of HOV-equipped freeways, it was found that limited-access HOV lanes appear to have a safety performance disadvantage when measured by collision distribution or collision rates for the HOV lane alone and for the HOV and left lanes combined. This paper...

This project examined the safety and demand issues for pedestrians and bicyclists at multi-lane roundabouts through a literature review, case studies, in-field counts and surveys, focus groups, and video analysis. This document presents research findings, synthesizes current information on best...

The objective of the study described in this paper is to identify common site features that may contribute to high collision rates under wet pavement conditions. To minimize falsely identified high collision concentration locations (HCCL) in evaluating factors contributing to high collision...