Safe Transportation Research & Education Center

This paper describes the results of simulation studies to determine how effectively left-turning drivers can be alerted to imminent conflicts with opposing traffic under difficult operating conditions and with limited detector capabilities. These conditions include approaching vehicles changing speed in locations that are not covered by detectors and detectors that may only be able to detect vehicle presence, but not speed. In cases without direct speed detection, one may try to rely on historical speed statistics to estimate the speed of approaching traffic, but unless the approach speeds are confined to a very narrow range the system is vulnerable to both false positive and false negative alerts in the respective cases of the real vehicle speeds being less than and greater than the assumed historical value.