This study uses a location and profile of the firms in the six-county Chicago region from 1981 and 1999 to compare the businesses’ proximity to freeway ramps and transit stations for those two time periods. A series of regression models were constructed to assess whether their location patterns with respect to transportation facilities have changed over the last two decades. The data suggest th...

A method is presented to divide the total congestion delay in a freeway section into six components: the delay caused by incidents, special events, lane closures, and adverse weather; the potential reduction in delay at bottlenecks that ideal ramp metering can achieve; and the remaining delay, due mainly to excess demand. The fully automated method involves two steps. First, the components of n...

This article studies the usefulness of parallel processing in real-time traffic-flow simulation based on continuum modeling of traffic dynamics. Computational fluid dynamics (CFD’s) methods for solving simple macroscopic traffic-flow continuum models have been studied and efficiently implemented in traffic simulation codes (on serial computers) in the past. We designed a traffic-flow simulation...

Increased emphasis has been placed on improving the explicit role of highway safety in making decisions on highway planning, design, and operations. This can be achieved by quantifying the safety effects of geometric design elements for various highway facilities. While great attention has been directed primarily on rural two-lane highways and to a lesser degree, on urban arterials and rural mu...

The paper characterizes the behavior of the cell transmissionmodel of a freeway, divided intoN sections or cells, each with one on-ramp and one off-ramp. The state of the dynamical system is theN-dimensional vector n of vehicle densities in theN sections. A feasible stationary demand pattern induces a unique equilibrium flow in each section. However, there is an infinite set—in fact a continuum...

While rural freeways generally have lower crash rates, interactions between driver behavior, traffic and geometric characteristics, and adverse weather conditions may increase the crash risk along some freeway sections. This paper examines the safety effects of roadway geometrics on crash occurrence along a freeway section that features mountainous terrain and adverse weather. Starting from pre...

Incidents on the freeway disrupt traffic flow and the cost of delay caused by the incidents is significant. To reduce the impact of an incident a traffic management center needs to quickly detect and remove it from the freeway. In this vein quick and efficient automatic incident detection has been the main goal of the transportation research for many years. Also many algorithms based on loop de...

This paper makes use of a probabilistic model, that predicts the likelihood of crashes (crash potential) on freeways on the basis of traffic flow conditions, in real-time crash prevention. The model was developed using incident logs and loop detector data collected over a 13-month period on the Gardiner Expressway in Toronto. The previous work suggested that an increase in levels of traffic tur...

In this paper, we present a model predictive controller to reduce road traffic congestion in freeway networks. The model predictive controller regulates traffic in the freeway through the use of ramp metering and variable speed limits. The controller uses a Link-Node Cell transmission model (LN-CTM) to represent freeway dynamics. We modify the standard LN-CTM to account for the capacity drop ph...