TAMPA, Fla. -- When the Tampa City Council hears a report from staff on the city's red light camera (RLC) program and yellow light intervals Thursday, there's a good chance they'll be learning a lot about traffic engineering in a short amount of time.
But if the presentation is similar to other RLC presentations across Tampa Bay in recent weeks, it'll be hard for the elected officials to follow all the "engineer-speak."
Intersections and traffic flow are calculated using complex equations. But the 10 News Investigators showed state - and some local - engineers were reducing yellow light times in a very simple way.
TIMELINE: 10 News' Short Yellows Investigation
Instead of calculating the yellow light times based on drivers' actual approach speed, most RLC intersections in Greater Tampa Bay are now calculated based on posted speed, which, according to numerous national studies, is inappropriate and dangerous.
It also used to be against FDOT rules to use posted speed in areas where cars travel faster than the speed limit, but in 2011, the agency reduced Florida's state minimums below federal guidelines, allowing for shorter lights.
For instance, in Tampa, 10 News showed how the yellow intervals at the intersection of 50th St. and Adamo Dr. were only 3.9 seconds - possibly the shortest intervals for any 40 mph approach in Tampa Bay.
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 Adamo Dr., would result in yellow light times of almost 5.0 seconds.
Other national studies have suggested up to another half-second added to yellow times in areas with lots of older drivers or truck drivers.
Short yellow lights can cause more panicked decisions, which can cause more accidents and more RLC citations.
In Tampa, more than $7 million in RLC citations were doled out last year. The state collects more than half of the revenue; the city and camera company split the rest.
Tampa Mayor Bob Buckhorn indicated the intersection timings were FDOT's problem, not his. But the Hillsborough Commission recently voted to request longer yellow lights at the RLC intersections in unincorporated areas of the county. Tampa City Council will take up the conversation Thursday morning at 10 a.m. at City Hall.
Yet as other communities discuss the issue, confusion over yellow times abound.
Manatee County Commissioner Betsy Benac was quoted in the Bradenton Herald as saying "We have to comply with state law...We don't have the option of jumping to federal law."
But actually, they do.
In the words of FDOT's top signal engineer, Mark Wilson, Florida's minimums, which typically fall below the national suggestions for intervals, "are just minimums." Wilson said local communities could ask for longer yellow intervals with an engineering justification.
FDOT indicated it would approve the "posted speed +7 mph" request -- or potentially greater, depending on which engineering study or rationales were cited.
The Manatee Board of County Commissioners, just like the two city councils - Tampa and St. Petersburg - that will discuss the issue Thursday, have an opportunity to request yellow intervals above the state minimum.
Already, Hillsborough County commissioners, Brooksville councilmembers, and South Pasadena city commissioners have all requested yellow lights longer than the state minimum.
FDOT already announced a statewide re-timing for all short yellow lights 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, but in most areas, the minimums will still not be enough to meet federal safety suggestions.
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