Safety Effectiveness of Actuated Advance Warning Systems

Abstract

Driver behavior within the dilemma zone can be a major safety concern at high-speed signalized intersections. The Nebraska Department of Roads (DOR) has developed and implemented an actuated advance warning dilemma zone protection system. This paper investigates the impact that system has had on safety at high-speed signalized intersections. The operating algorithm has been designed such that the system continually monitors an upstream detector, as well as traffic at the intersection, to predict the onset of the yellow signal indication. Flashing beacons are used to warn drivers of the impending end of the green indication. Although these systems have received positive reviews from the public—and commercial vehicle operators in particular—there has been no comprehensive analysis of their effect on safety. The focus of this research was to address this evaluative need and provide answers about the effectiveness of the Nebraska DOR system in improving safety. Crash records from before and after the implementation of the system at 26 intersections were compared. In addition, 29 control intersections were used to compare crash rates over time, and a fully Bayesian technique was employed to ensure that no exogenous variables affected the study. Results of the analysis were promising (an overall crash reduction rate of 8%) and suggested that the use of the system should be encouraged as an effective safety treatment for the dilemma zone problem at high-speed signalized intersections.

A Review on Drivers’ Red Light Running Behavior Predictions and Technology Based Countermeasures

“…The actuated advance warning system has an uninterrupted traffic monitoring facility in the dilemma zone and was introduced by The Nebraska Department of Transportation in the USA to predict the yellow onset at the signalised intersection. The actual advanced warning system can notify the driver of the SAG decision via signs and flashing signals based on the prediction [89][90][91]. A disadvantage of this technology lies within the signal display.…”

Operational Evaluation of U-Turns at At-Grade Signalized Diamond Interchanges

“…Separating U-Turns from Conflicting Traffic. Separating U-turns from conflicting movements at departures is expected to improve U-turn performance as indicated by Figure 2b and evaluation results of countermeasure Number (4), (5), and (9). Researchers further evaluated the combined effect of several countermeasures of separating conflicting traffic from U-turn departures at the site I-45 @ Rayford Road.…”

“…Microscopic simulation was the major means of evaluating base conditions and proposed solutions in this study because of the wide variety of site characteristics and the large number of scenarios considered. Studies have shown the capability of well-calibrated simulation models to compare diverse operation scenarios as required for this analysis ( 8 – 10 ). Of the original 26 study sites selected, one of these was omitted because of a lack of the necessary site data.…”

Prediction of Red-Light Running on Basis of Inductive-Loop Detectors for Dynamic All-Red Extension

“…This system has an uninterrupted traffic monitoring facility in the dilemma zone, and it predicts the yellow onset at the signalised intersection. It can notify the driver of the stop-go decision via signs and flashing signals based on the prediction (Appiah et al, 2011;McCoy & Pesti, 2002;Naik et al, 2019). But the negative side effect often reveals when the drivers misconstrue the flashing signal and stop immediately instead of regarding this as a warning signal in advance (Factor et al, 2012).…”