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Alternating blank out signs installed at rail crossings near Denver resulted in a 61.3 percent reduction in crashes.

Case study finds that alternating blank-out signs are effective in decreasing the frequency of violations and risky behaviors at at-grade crossings as they provide a clearer message to motorists of the risk of making a turn.

Date Posted

New MUTCD Sign: Safety Study of Motorist Behavior at Grade Crossings

Summary Information

Five of the Light rail transit (LRT) crossings on the Denver Regional Transportation District (RTD) Central Corridor are located adjacent to and near the Auraria Campus, which houses the University of Colorado Denver, Metropolitan State University, and the Community College of Denver. These five crossings experience high traffic volumes with use by many pedestrians and bicyclists, and have shown some of the higher crash volumes on the entire RTD LRT system.

In 2012, blank-out signs activated upon train detection were installed at each of the five crossings. The assessment evaluated the behavior of motorists making a Right Turn on Red before and after the installation of the new blank-out sign that illuminates and alternates the "Light Rail Transit Approaching" and "No Right Turn" symbols when activated by an approaching train. A surveillance camera was used for gathering "before" and "after" motorist behavior data at the existing at-grade crossings. One day of data was collected before the installation of the new blank-out sign and one day of data was collected after the installation. The pooled datasets include recordings of 15 hours each day, from 7 AM to 10 PM.


  • The before/after analysis appears to show that the new alternating blank-out signs were effective in decreasing the frequency of violations and risky behaviors at at-grade crossings, as seen in the table below.

Traffic violations per category



Traffic violations per category
Did not stop at stop bar
Stopped on track
Total RT traffic violations



  • There was a preliminary reduction in crashes of 61.3 percent at the five study crossings in the Cascades after installation of the new alternating blank-out signs.
Goal Areas
Results Type
Deployment Locations