Are strobe lights allowed in red signals?
No, they are not allowed. Section 4D.06 of the 2009 MUTCD specifically prohibits strobes within or adjacent to any signal indication. Research and experimentation over the years with white strobe lights as a circular “halo” outer ring around the red signal or as horizontal bar across the red signal has found no lasting safety benefit and, in some cases, the strobes resulted in increased crash frequency. Based on this experience, FHWA made a determination in 1990 no further experimentation with strobe lights in traffic signals would be approved and that all existing strobes were to be removed. In 1995 a report by the Virginia Transportation Research Council provided an updated review of strobe light effectiveness in the States where they had been used. That report validated the previous analyses and came to the same basic conclusion, that there is no evidence that strobe lights are consistently effective in reducing crashes. Therefore, it is still FHWA’s position that strobe lights are
