Wireless Video Camera Gets the Green Light
Ever waited at an intersection for that left-turn light that never comes, wondering why the sensors in the road are blatantly ignoring you, just as your kids do?
It’s not you. It’s the intersection.
Most intersections have wires underneath them that emanate a magnetic field that projects about 3 feet above the ground. Break that field, which requires something metal about the size of a wheel axle, and a signal is sent to a box at the street corner to change the light.
But the wires are fragile. Changes in temperature cause them to contract and expand, careless road crews might cut them, and, well, it’s not easy living under pavement.
At any given time, about a third of those sensors don’t work, said Don Sinnar, senior vice president of Odetics ITS, a subsidiary of Anaheim-based Odetics Inc.
In the early 1990s, the industry began using video cameras to detect when a car is waiting at an intersection. The cameras used technology that helped distinguish between a shadow moving across a lane and a vehicle, and identify a car during low-visibility times such as dawn, dusk and fog.
Now the industry is moving to wireless video camera detection, and Odetics introduced its system last week. The system shares the same band that high-end cordless phones use, but with a different language.
Making the system wireless reduces installation and maintenance time and costs, Sinnar said.
“The result should be better allocation of green time,” Sinnar said in that cool traffic-engineering lingo. “You should be flowing more efficiently through city streets and you’re not going to come to that nonworking left-turn light because the detection site has gone out of service.”
You can identify intersections still using the in-pavement systems by the circles cut in the lanes, but video detection last year had 39% of the market, Odetics officials said, citing a study by Transport Technology Publishing, an industry publication.
The video cameras may seem susceptible to damage from the elements, but Sinnar said that they have only had one camera returned because of physical damage.
“They shot it. And it took them three shots,” Sinnar said.
That’s fair warning to those traveling through Fairfax, Va.
Odetics’ wireless units cost about $20,000 per intersection, Sinnar said. The traditional in-pavement technology cost about $1,000 per installation, with some lanes having three or four installations each.
Earlier this year, Odetics signed the city of Santa Ana to a $220,000 contract to implement a wireless video-based vehicle detection system.
The global market for these traffic-detection systems currently exceeds $5 billion, according to Transport Technology, with Odetics facing competition from the likes of Image Sensing Systems Inc. of St. Paul, Minn., and Waltham, Mass.-based Thermo Electron Corp.
