U.S. Department of Transportation
400 Seventh St., S.W.
Washington, D.C. 20590

July 2, 2003
Refer to: HOTO-l

Mr. Lap T. Hoang
State Traffic Operations Engineer
Florida Department of Transportation
605 Suwannee Street, MS36
Tallahassee, FL 32399-0450

Dear Mr. Hoang:

This is in response to your June 10 note to Mr. Scott Wainwright of our staff concerning the use of strobe lights within red traffic signals. You asked whether strobe lights in traffic signals are approved traffic control devices in the Manual on Uniform Traffic Control Devices (MUTCD). The following Official Interpretation is made in response to your request.

There are no provisions in Part 4 of the MUTCD that allow the use of strobes within red traffic signals. Based on the research done to date with strobe lights that found no lasting safety benefit, the Federal Highway Administration (FHWA) made a determination in 1990 not to approve any further experimentation with strobe lights in traffic signals, and to terminate all then-current experimentations with these devices. In 1995, a report by Mr. Benjamin Cottrell of the Virginia Transportation Research Council provided an updated review of strobe light effectiveness. 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 accidents. Therefore, it is still FHWA's position that strobes in traffic signals are not approved traffic control devices, and we do not plan to add them to the MUTCD. The FHWA also does not plan to approve any further experimentation with strobe lights in traffic signals.

There are still strobes operating within red traffic signals in a variety of states and local jurisdictions, but they are not in accordance with the MUTCD and they are not under any approved experimentation. There are no approved experimentations with strobes in Florida, and it is our recommendation that any strobes in place should be removed.

For reference purposes, we have numbered and titled this Official Interpretation as 4-263(I)- "Strobes Florida DOT." I hope this information is useful to you. If you need additional information, please feel free to contact Mr. Scott Wainwright at 202-366-0857.

Sincerely yours,

Vincent Pearce
Acting Director, Office of Transportation
cc: Mr. Jim Baron, ATSSA
Operations