POLK COUNTY, Florida -- Short yellow lights set are likely ticketing more drivers than they should along US-27 in Haines City. And the 10 News Investigators have discovered some of the timings may not even comply with the state's low minimums.
The discoveries are the latest from the 10 News Investigators, who have been exposing yellow light reductions by the Florida Department of Transportation (FDOT), particularly at red light camera intersections.
WATCH: Initial Short Yellows Investigation
TIMELINE: 10 News' Short Yellows Investigation
Haines City turned on 13 red light cameras (RLC) at seven intersections in January 2011. But a pair of those intersections were re-timed last summer to reduce the length of the yellow lights.
The yellow interval on US-27 at Davenport/Sanders, a 55 mph zone, was reduced from 5.5 seconds to 5.0 seconds. And the yellow intervals on US-27 at Holly Hill/Massey, also a 55 mph zone, was reduced from 6.0 seconds to 5.0 seconds.
Furthermore, the southbound approaches of those two intersections appear to be slightly downhill. The state requires yellow lights lengthened by a fraction of a second on downhill approaches, meaning both aforementioned intersections are out of compliance with the state's Traffic Engineering Manual (TEM).
U.S. Department of Transportation guidelines also recommend a grace period for drivers who violate the red signal after a yellow light length is reduced. But Haines City kept ticketing drivers, even if they were used to a longer yellow light and got "caught" by the new intersection timings.
The Haines City Police Department says neither its agency nor the city was notified by FDOT of its timing changes in June 2012; FDOT simply made the changes and provided the new information to American Traffic Solutions (ATS), the leading red light camera company.
ATS tells 10 News it has nothing to do with yellow light timings. But a full analysis of Haines City's RLC indicates all of its yellow lights are now set to intervals calculated by the posted speed limit.
Numerous federal studies discourage the use of posted speed limit in yellow light calculations, and a recent report from the National Cooperative Highway Research Panal (page 11 of this PDF) suggests using posted speed limit plus 7 mph or more, which along US-27, would add approximately half a second to the yellow light times.
Other federal standards suggest up to another half-second for areas, like US-27, with lots of truck drivers. Short yellow lights can cause more panicked decisions, which can cause more accidents and more RLC citations.
FDOT tells 10 News local cities or counties could request longer yellow lights, provided "engineering justification from a Florida (engineer) that provides the reason for the request."
Haines City and Polk County engineers could request intervals be calculated based on the "posted speed +7 mph," as suggested by a recent national study.
FDOT also announced an across-the-board change to state minimums for yellow light timings, following 10 News' investigation. The state will add 0.4 seconds to all yellow light minimums to better accommodate the state's older driving population.
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