Civil and Environmental Engineering


Date of this Version



Transportation Research Record (2011) no. 2259: 253-263. DOI: 10.3141/2259-24.


Copyright 2011, Transportation Research Board of the National Academies. Used by permission.


A series of innovations has been made in the vehicle sensors field. Technologies such as IntelliDrive and radar-based smart sensors make it pos­sible to track each vehicle in proximity to an intersection. However, current technologies have limitations, such as lack of robustness, accuracy, or level of penetration. This paper assumes an accurate wide-area detector (WAD), which might be soon available, and highlights the potential benefits that might be derived in safety and efficiency of oper­ations at high-speed intersections from the deployment of the WAD. Two critical areas in which wide-area detection can lead to significant improvements are discussed: (a) location of crash risk on onset of yellow and (b) location of vehicles on onset of yellow. A case study was conducted at an instrumented intersection in Noblesville, Indiana, to esti­mate potential improvement from the use of an ideally operating WAD and green extension logic for signal control. Findings revealed that the replacement of the single loop detector sensor with a WAD sensor would lead to an additional 1.4 vehicles being served per lane on the cross street per unit vehicle provided with dilemma zone protection on the high ­speed approach. Results also showed that speed traps should be used only after accounting for the trade-off between safety and efficiency and the traffic control logic. When speed traps were designed with generic dilemma zone boundaries at the Noblesville site, the dilemma zone protection was provided only 57% of the time because vehicles accelerated or decelerated after passing the speed trap.