Within the City of Tucson’s nearly 227-square miles, there are 30 locations waiting to snap your photo. But you don’t have to smile because those photos are taken only if you violate the traffic rules enforced by red light cameras at select intersections.

By law, the city must clearly mark all intersections with red light cameras by postings signs indicating the intersection is photo enforced. Of the 30 red light cameras in the city, 13 of them also are speed enforcement cameras.

Other jurisdictions — Oro Valley, Marana and Pima County — have chosen not to install red light cameras at any of their intersections, but rather enforce red light rules through police and deputy patrols.

The red light cameras in Tucson are activated by sensors that detect when a vehicle runs a red light by taking high resolution photographs of the vehicle license plate and also the driver as the vehicle passes through the red light.

According to the Tucson city website, where a Tucson Police Department spokesperson referred The Explorer when asked for comment, “You will only receive a ticket if you enter the intersection after the signal turns red. According to the law, a vehicle must stop when facing a red light before entering the intersection. Entering the intersection is defined as the vehicle passing the lateral prolongation of the curb line, or the line between the curbs on each side of the street.”

Notably, such lines are imaginary and often not always depicted on the pavement.

The Tucson website information continues, “If you have passed this line when the light turns red, you are legally in the intersection. It is good driving practice to not speed up into an intersection in an attempt to be past the curb extensions when the light turns red.”

The U.S. Department of Transportation Federal Highway Administration (FHA), in defining an intersection, states on its website that “A driver is running a red light if his or her vehicle enters (the red shaded area pictured) after the light turns red. According to the Manual on Uniform Traffic Control Devices (MUTCD), the boundary for a red light violation begins at the marked stop line. If there is no stop line, then the boundary begins at the crosswalk on the near side of the intersection. If there is no crosswalk or stop line, the intersection begins at the extension of the curb line or roadway edge.”

The FHA website continues, “Some states are using the extension of the curb line to mark the boundary for red light running regardless of whether there are stop lines or crosswalk. This practice is not consistent with the meaning of the red signal in the MUTCD.”

Efforts were made by the state legislature in 2012 in a bill sent to Governor Jan Brewer to get rid of the imaginary lines set across the crosswalk at intersections, but the bill was vetoed by the governor.

The Tucson website red light information also takes on the issue of the timing of the yellow light at intersections. It states, “All of the yellow lights in Tucson comply with federal standards for yellow light length. This means that if you are traveling the speed limit, adequate time exists for you to go through the intersection at a constant speed before the light turns red or for you to safely stop before the red light.  As the driver, you will need to make the judgment as to which is the best course of action. If you feel you have to speed through an intersection, one of the most dangerous places to speed, you consider a safe stop as an alternative.”

City engineers maintain through the website that the timing of all lights in the city follow established guidelines “set by the Institute for Transportation Engineers and adopted by the Federal Highway Administration in the Manual for Uniform Traffic Control Devices.”

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"City engineers maintain through the website that the timing of all lights in the city follow established guidelines “set by the Institute for Transportation Engineers and adopted by the Federal Highway Administration in the Manual for Uniform Traffic Control Devices.”

These guidelines are the problem. By opposing the laws of physics, adherence to them causes drivers to inadvertently run red lights.

CBS report: http://wtkr.com/2014/02/04/red-light-camera-traps-does-physics-prove-our-yellow-lights-are-too-short/

Traffic Technology International Article: http://viewer.zmags.com/publication/ecd7d66f#/ecd7d66f/1


The camera companies bank, and make bank, on the confusion around the intersection definition. Arizona is the only state that has this definition. The cities fought the law change to be like the other states because they know it will cut into their ticket revenue and they got Brewer to veto it. There is no compelling reason to be different than the other states.
Also, while the light timing may meet the standards, the timing is set at the MINIMUM. The minimum is NOT optimal for safety, it is typically higher. But the city doesn't care about this, they want MONEY, not safety.

John Flanagan

Between traffic cameras, drones overhead, computer hackers, government snooping, IRS audits, and other things, life is much more complicated today then when I started out 69 years ago. I suppose it will get even worse in the future.

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