The current practice of specifying simultaneous gap out logic at isolated high speed signalized intersections places constraints on the signal controller logic that cannot be satisfied under high congestion level. Further, it often results in degraded signal efficiency and dilemma zone protection. A stochastic approach is proposed in this paper with the objective of increasing safety and effici...

Introduction Perceived waiting time (PWT) at signalized intersections differs from the real value of waiting time (WT), and varies with signal design. The onerousness of delay depends on the conditions under which it is experienced. Using weighted travel time may contribute to optimal signal control if its use can improve upon assuming that all time is weighted equally by users. This research e...

This paper addresses the optimization of the green light durations in a signalized urban area, by means of a traffic-responsive control strategy. The adopted model, mainly consisting of signalized intersections and roads, is microscopically represented by means of deterministic-timed Petri nets (DTPNs), which allow a compact representation of the traffic behaviour. The proposed optimization alg...

Delays that individual vehicles may experience at a signalized intersection are usually subject to large variation due to randomness of traffic arrivals and interruption caused by traffic signal control. While such variation may have important implications for the planning, design and analysis of signal controls, currently there is no analytical model available to quantify it. This paper descri...

In many cases, crashes at intersections account for over 50% of all urban road accidents. The need to reduce these crashes has fostered considerable research on the development and evaluation of traffic safety at intersections. This paper introduces a micro-level behavioral method for estimating crash potential at signalized and unsignalized intersections for different traffic characteristics. ...

The Highway Safety Manual [HSM, 2010] recommends safety evaluations be performed before implementing any roadway treatment to predict the expected safety consequences. Safety consequences can be measured using crash prediction models, Crash Modification Factor (CMFs), or both. This paper develops a CMF to show the expected impact of red-light cameras (RLCs) on safety at signalized intersections...

Optimally minimizing delay times at signalized intersections can significantly improve both traffic flow and safety. However, most traffic flow optimizing tools do not measure the effect on safety. This study uses nonlinear programming (NLP) algorithms to optimally minimize delay times and employs both Safety performance functions (SPFs) and empirical Bayes (EB) before-after methodology to meas...

OBJECTIVE To estimate the effects of red light camera enforcement on per capita fatal crash rates at intersections with signal lights. METHODS From the 99 large U.S. cities with more than 200,000 residents in 2008, 14 cities were identified with red light camera enforcement programs for all of 2004-2008 but not at any time during 1992-1996, and 48 cities were identified without camera program...

This project was conducted to investigate new concepts, new tools and emerging technologies directed at enhancing traffic operations and safety on signalized urban arterials that operate under saturated conditions. McFarland Boulevard, a six-lane urban arterial running north-south through Tuscaloosa, AL served as the research focus and test bed for the project. There are nine urban intersection...