A red light camera in Arnold, Missouri ticketed a man faced with both a yellow and a red light simultaneously. Motorist Mike Crawford saw the yellow light at the intersection of 141 and Astra Way at 1:40pm on July 4 and proceeded through in safety. Weeks later, he received a citation in the mail demanding $94.50. In challenging the ticket, Crawford noticed the photograph showed both yellow and red lights illuminated. While an administrative hearing officer dismissed the violation, Crawford remained upset by the process because he was put in the position of proving himself innocent.

"We're innocent until proven guilty and that (red light camera) ordinance violates that," Crawford told KSDK television in an interview. "You're guilty by the virtue of the fact that you own the vehicle that has gone through the red light and you have to prove that someone else was driving the vehicle."

Crawford's citation was likely caused by a combination of factors. First, Arnold's red light camera program is set to trigger citations a split-second after the light turned red. In this case, the trigger is set to so short a time, likely one-tenth of a second, that the signal shown on the left of the photo changed from yellow to red before the signal seen on the right did so.

The Arnold ticket was no fluke. The highwayrobbery.net website has documented a number of similar simultaneous red and yellow tickets in California and traced the cause to a second factor -- the difference in speed between an LED bulb and a slightly slower incandescent bulb. If one signal head uses an LED and another an incandescent bulb, tickets can issue in cases equivalent to running a "red" light in the amount of time it takes for a light to appear after flipping a switch -- an amount so small that it is not detected by the human eye.

According to a report by the California State Auditor, about four out of every five red light camera citations in the state were issued for split-second violations. Shorter trigger settings or "grace periods" allow jurisdictions to collect more revenue because the greatest number of technical violations occur within the first 0.25 seconds after a light turns red, according to a Texas Transportation Institute study. Ticketing such violations has little impact on safety as the same study showed the probability of a right-angle collision within a split-second after a signal changes from yellow to red is almost zero at an intersection with a protected left turn lane. "Given a 1.0-second all-red interval, the probabilities also suggest that crossing through vehicles will not start to enter until after about 4 seconds have lapsed," the Texas study explained (page 99).