There are guidelines for how long a traffic control signal must remain yellow. In the City of New York, for example, the NYC Administrative Codes requires that yellow lights remain in the yellow phase for 2 to 3 seconds.
Obviously, the length of time that a yellow light is illuminated is important to providing adequate notice to drivers about the impending red phase. If a driver is short-changed by his or her yellow light, then a viable defense is raised to defeat a disobey red light ticket.
A man in Collier County, Florida, recently used this theory to actually beat his wife’s red light traffic ticket. Armed with only a stopwatch and a complaint from his wife that it was a “quick yellow”, Mike Mogil, a math tutor by trade, went to the subject intersection and timed the subject traffic control signal 15 times coming up with an average length of 3.8 seconds. Because county guidelines required yellow lights to be, at least, 4.5 seconds, his evidence was sufficient to convince the judge to dismiss his wife’s traffic ticket.
If you are issued a red light ticket at an intersection with a “quick yellow”, knowing the law and timing the light can help you avoid 3 points and a $250 fine.