Government Technology - November 2008 - (Page 36)

justice of speeds that is harmful where people are merging, getting off, changing lanes, that kind of thing.” In Seattle’s yearlong pilot, results showed red light running decreased by 50 percent at the four intersections where cameras were present, according to Mike Quinn, strategic adviser to Seattle Police Chief Gil “If as a byproduct, we more than break even and have more dollars to go to our general fund purposes, that’s OK.” Mike Quinn, strategic adviser to Seattle Police Chief Gil Kerlikowske present much tougher safety situations than others. Some have good sightlines in all directions; others have terrible sightlines, and if you make a bad judgment, it could be lethal because you can’t see.” That variance among intersections, along with the negative results of some red light camera deployments, led the Colorado Department of Transportation (CDOT) to lean toward re-engineering of intersections rather than using red light cameras, said Jake Kononov, director of research for CDOT. “Prior to installing the red light cameras, we ought to examine accident causality and the reason for overrepresentation [in red light running or accidents] and if nothing else works, which is unlikely, then let’s talk about the red light cameras,” Kononov said. Timing is Everything In Aurora, Colo., accidents increased by 36 percent in 2006 at four intersections where cameras were installed. In Fort Collins, Colo., 10 years after a camera was installed at one intersection, accidents had increased there consistently. After the timing of the yellow light was increased by one second, crashes dropped 29 percent and tickets fell from 166 a month to 21 per month. Yellow light timing is one of several factors that could lead to a dangerous intersection, Kononov said. “If we [CDOT] see a pattern of broadsides, we may observe that the yellow plus red light interval is not properly timed or you have something blocking the signal head. If we have an unusually high number of broadsides, it is not because we have bad drivers; it’s probably because there is something about this particular intersection, such as signal-head visibility or arterial progression; these are the kinds of issues that lead to overrepresentation of broadsides.” There are federal guidelines for how long the yellow light should be, and most states and municipalities follow them. It’s usually three to five seconds. It’s recommended that yellow light times are one second for every 10 mph. Kononov said there’s no reason to go below the three-second mark, and extending the yellow can make a big difference. In Dallas, for example, the city shut down a quarter of its red light cameras because the city cameras weren’t bringing in revenue after the city extended the yellow light interval. Quinn said the Seattle Department of Transportation considers many alternatives Technology Upgrade The ﬁrst red light cameras used ﬁlm and radar and generally weren’t very practical to use. That has changed. Though radar is still used, in-ground loops and sensors more accurately record the speed of individual cars, and digital photographs have replaced ﬁlm. The loops and sensors are buried in the street and measure a vehicle’s speed, signaling the camera. While radar is confused by dense trafﬁc, sensors can be placed in each lane and catch individual speeders or red light runners. Two sensors are placed at intervals in each lane to record the vehicle’s speed as it nears the intersection and signal the camera that a car is approaching too fast to stop in time. Wireless vehicle detectors — an even newer technology — are less intrusive than the sensors, which require the street to be dug up. The wireless detectors are the size of a tuna can and ﬁt just under the street surface. Like the sensors, they provide a point-to-point distance calculation that signals the antenna on the red light camera pole. The camera records images of the vehicle, including a shot of the license plate and a 12-second video. The data is sent to the vendor, which checks the images and video for quality, then turns the images over to the city’s enforcement agency, which mails the ticket to the car owner. NOV_08 Kerlikowske. “We also found that the severity of accidents decreased as well,” he said. That would suggest a drop in the number of broadside collisions. Opponents of red light cameras suggest that a decrease in the broadside collisions (one of the most common and dangerous types of accidents) coincides with an increase in rear-end crashes as drivers slam on their brakes to avoid going through red lights. But Seattle’s pilot found no increase in rear-end collisions, Quinn said. “That’s worth noting because that’s not what we’ve seen from other research nationally,” he said. The goal of expanding the program is to reach a point where motorists drive safely on a consistent basis. “As we get the technology more uniformly present in the city, I think driver caution will increase even more than it has to date,” Quinn said. Seattle placed six cameras at four intersections where red light running and broadside accidents were relatively frequent and had positive results from all of the intersections. “They all had plenty of business,” Quinn said. But that doesn’t mean the answer to an unsafe intersection is necessarily a red light camera program. The geometry of intersections varies, and those variations can impact safety. “They’re not all created equal,” Quinn said. “Some 36 http://www.govtech.com

Table of Contents Feed for the Digital Edition of Government Technology - November 2008

Government Technology - November 2008 Contents Point of View On the Scene Big Picture Four Questions for … Forward Thinkers Taking Tech Home Virtual Frontier Hidden Costs Uncovered Seeing Red For the Record In the Loop Benign Dictatorship Home-Field Advantage A Better Way to Park New Tools for Fighting Crime How It Works Spectrum Products Two Cents signal:noise

Government Technology - November 2008

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