Traffic engineers: intersection bill safety concerns overblown
Published: May 1, 2012 at 6:06 pm
Despite safety concerns that some police officers have raised about changing the definition of intersections in Arizona, traffic engineers from the state’s two largest metro areas said small changes to traffic light timing should address at least some of those concerns.
House Bill 2557 seeks to expand the definition of an intersection to include the crosswalks. The Senate on Monday gave final approval to the bill and it awaits a signature or veto from the governor.
Because drivers would get a small amount of extra space to enter the intersection, fewer drivers would be cited for running red lights, particularly where red-light cameras are equipped to catch those violators.
That led veteran traffic police and the director of the state police training board to conclude that the bill would lead to more injuries and fatalities, since people would be given slightly more time to get into an intersection before they would technically be running a red light.
But Ron Doubek, a Phoenix traffic signal engineer, and Andrew McGovern, a Tucson traffic engineer, said engineers in cities can adjust traffic-signal timing to alleviate dangerous situations.
“What it’s going to require us to do is look at all 1,100 of our traffic signals and revise the length of time for our all-red interval,” Doubek said of the moment when all drivers have a red light.
That all-red interval, which prevents drivers from being given a green light before all other vehicles have passed through the intersection, is calculated based on intersection size, the traffic engineers said.
Doubek acknowledged, however, that even with the change in the all-red interval, the redefinition of an intersection will mean that some drivers who would currently be considered running a red light will no longer be breaking the law.
But he said that change will only apply to those who would currently be guilty of running a red light by a split second.
“We’re only talking about a tenth or a 50th of a second, which is the blink of an eye,” Doubek said.
Doubek said the more aggressive red-light violators, who enter an intersection a half second or more after a light has turned red will still be cited by the red light cameras.
But he’s still concerned that drivers who learn of the change could adjust their driving in a way that results in more dangerous intersections.
“My fear is that this may give people the feeling that, ‘oh, I’m getting a free zone. I’m not going to get a red light ticket,’” Doubek said. “I would hate to give the public the impression that we’re giving them a little bit of slack.”