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FAQ # 6

Red Light Camera Studies:
Alternatives to Cameras

Updated 11-20-09

Engineers who have studied red light running - those who do not stand to gain financially from the use of red light cameras - suggest that cities try alternatives to cameras before installing cameras.  Why is that, and what are the alternatives?

Part (A) of Answer:  One alternative is to lengthen the yellow light, which is known to dramatically reduce the number of cars running the lights.  One study - details below - showed a 69% decrease in violations when a yellow was increased from 4.0 seconds, to 4.5 seconds.  Other studies - details below - gave similar results, and also rated engineering countermeasures such as longer yellows "most effective" in reducing unintentional running while enforcement, including cameras, was considered "less effective."

"It has frequently been claimed that if the yellow is 'too long,' more drivers will use part of the yellow as green. More drivers - it was argued - would cross after yellow onset with long than with short yellow."
"The data show that the percentage of last-to-cross vehicles clearing the intersection (T+0.2) seconds or more past the yellow onset was not appreciably changed by the extension of the yellow phase." ["The Influence of the Time Duration Of Yellow Traffic Signals On Driver Response," Stimpson/Zador/Tarnoff, ITE Journal, November 1980]

"Research has consistently shown that drivers do not, in fact, adapt to the length of the yellow." [Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985]

"Olson and Rothery reported in 1972 that their research showed that drivers were 'virtually' certain to stop if their required deceleration rate was less than 8 feet per second squared [ 0.25 G ] and virtually certain to continue if the deceleration rate required was in excess of 12 feet per second squared [ 0.38 G ]." [Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985]

Part (B) of Answer:  Another alternative is to improve street markings.  2005 research sponsored by the Florida Department of Transportation concluded (at page 69) that improving street markings near intersections would reduce red light running by up to 74 percent.  A large red light camera study sponsored by the San Diego Police Department rated engineering countermeasures such as better markings as "most effective" in reducing unintentional running whereas enforcement, including cameras, was considered "less effective."  (Farradyne, Table 6.3, p. 80.)

A couple more engineering countermeasures are larger signal lamps (12" dia. instead of 8") and, where there is no signal light on the "near side" of the intersection, adding one.