Evaluating Long-Term Effectiveness of Blank-Out Overhead Dynamic Advance Warning Signals

The Utah Department of Transportation (UDOT) installed advance warning signal systems on several approaches to high-speed signalized intersections after maintenance crews and other UDOT officials expressed concerns about safety at these types of intersections. The system designed and installed incorporated both advanced detection and advance warning signal components including blank-out signs with flashers mounted over the roadway as opposed to standard advance warning signs mounted on the side of the road. The new design was referred to as the blank-out overhead dynamic advance warning signal (BODAWS) system. UDOT contracted with researchers at Brigham Young University to evaluate the effectiveness of the BODAWS system. The metrics for evaluation included safety impacts through crash and red-light running differentials, as well as an evaluation of the impact on speed trends before and after activation of the BODAWS sign and flashers, particularly just prior to and immediately after the onset of the yellow change interval. The results of the evaluation indicated that the BODAWS system affected motorist behavior, although not all of the changes were positive. It was theorized that the warning that motorists received with the initial design came too far in advance of the onset of the yellow change interval leading motorists to believe that the warning did not need to be obeyed. As a result, the recommendation was made to set the timing of the lead flash of the BODAWS sign and flashers as a function of the decision zone, which was implemented with positive results.


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 16p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01049342
  • Record Type: Publication
  • Report/Paper Numbers: 07-0783
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 5:22PM