Evaluation of the Effectiveness of Blank-Out Overhead Dynamic Advance Warning Signal Systems Evaluation of the Effectiveness of Blank-Out Overhead Dynamic Advance Warning Signal Systems
The blank-out overhead dynamic advance warning signal (BODAWS) system reduced RLR at the site during the time period immediately after installation. Eight months later, the number of RLR violations was slightly higher on one approach than before BODAWS system installation.
Crash results showed that six months after BODAWS installation, the number of crashes declined at the study site. The number of crashes proportionately declined at the control intersection as well indicating a need to continue to evaluate and monitor changes.
Mean vehicle speeds recorded before the onset of the yellow signal increased on the approaches to the study site immediately after BODAWS installation, and remained higher eight months later. Mean vehicle speeds recorded during the yellow signal, increased eight months after BODAWS installation to speeds higher than before the system was installed.
Higher speeds during the yellow signal, combined with an increase in the number of RLR violations eight months after BODAWS installation, suggest that motorists may have begun to use the advance warning to speed up in an attempt to enter the intersection before the signal turned red. It is recommended that the lead flash time between activation of the BODAWS signs and flashers and the onset of the yellow signal should be adjusted so that motorists are not provided with more time than is necessary to safely clear the intersection.
School:Brigham Young University
School Location:USA - Utah
Source Type:Master's Thesis
Keywords:advance warning signal aws bodaws detection red light running signalized intersection safety crashes high speed
Date of Publication:05/03/2006