Red light running all but disappeared at a New Jersey intersection after the duration of the yellow light warning time was increased under threat of a lawsuit. Glassboro gave the private company American Traffic Solutions (ATS) permission to issue red light camera tickets at the intersection of William Dalton Drive and Delsea Drive on March 26. The location was so successful at issuing $85 tickets that it generated $1 million worth of notices within just seven months.

On average, 90 percent of these citations were issued to drivers in the right-hand lane mostly for making slow, rolling turns. On average, there were 191 tickets issued each month in the other lanes for alleged straight-through and left-turn violations that most consider to be red light running. Data generated by ATS and provided under a freedom of information request did not separate straight-through and right-turn violations.

Through violations plunged after ATS mailed a ticket to Mike Koestler, the former mayor of Harrison Township, for an alleged offense that took place in Glassboro. Koestler's investigation led to the discovery that the 3.0 second yellow time on the westbound approach of the intersection was in violation of state signal timing regulations. On October 26, the borough boosted the yellow time to 4.0 seconds.

In November, the first full month following the change, the number of tickets issued in the non-right-turn lanes dropped 88 percent to 23 tickets issued. The figure dropped to 8 in December and was just 13 in January 2011. For just the westbound approach, the average number of tickets dropped from 71 per month to zero tickets through January.

While a one-second difference in the duration of the yellow warning at an intersection might seem insignificant, the extra margin of safety is critical. The vast majority of straight-through red light "violations" happen when drivers misjudge the end of the yellow light by less than 0.25 seconds -- literally the blink of an eye (view Texas Transportation Institute (TTI) chart). In most cases, a yellow shortened by one second can increase the number of tickets issued by 110 percent, according to a TTI report. Confidential documents uncovered in a San Diego court trial prove that the city and its private vendor, now Affiliated Computer Services (ACS), colluded to install red light cameras only at intersections found to have short yellow times (view documents), thereby maximizing profits. Yellow time generally does not affect the number of right-turn tickets issued.