City's video fights traffic congestion

This story appeared in the Antelope Valley Press March 5, 2001.

By BOB WILSON
Valley Press Staff Writer

PALMDALE - In a small room on the second floor of Palmdale's Development Services building, traffic engineer Tom Horne sits and watches his big-screen TV.

Horne isn't watching daytime TV, but is monitoring what's happening at 22 of the 75 city intersections with traffic signals.

And Horne doesn't issue tickets from his city room, nor does he record vehicle mishaps or purposefully change the signals to annoy motorists.

Via video cameras mounted on light standards, he keeps an occasional eye on traffic flow, noting which signals need repairs and which could use adjustments to make traffic flow easier and faster.

The city has neither the staffing, the equipment nor the inclination to watch or record what happens at all the monitored intersections, Horne says.

That would take "about 350,000 tapes a year and somebody dumb enough to sit here and change them all," he said, chuckling. "Go sit at an intersection for a while - it's not all that exciting."

But the city does have the inclination to ease street congestion, improve traffic safety, decrease air pollution and even cut gasoline costs for its motoring residents.

Because of the installation of a $1.9 million, grant-funded system that uses fiber-optic cables to link City Hall with intersection-mounted cameras and signal controllers, smog has been reduced by 1.97 tons a year and fuel efficiency increased from 18.27 to 25.28 miles per gallon along Rancho Vista Boulevard, according to an analysis by Minager & Associates of Irvine.

The first grant helped the city hook its TV monitor to most of the traffic signals along Rancho Vista Boulevard and 10th Street West. Two more grants will help the city do the same in the next couple of years with the signals along Avenue R and Avenue S.

Of 75 signals in the city, 44 are under sole municipal control, Horne says. That number includes most of the signals along Rancho Vista Boulevard, fifth and 10th streets west, 25th Street East, avenues R and S and Pearblossom Highway.

Other signals, such as those along Palmdale Boulevard, are under the control of the California Department of Transportation, and a few are under the control of Los Angeles County or the city of Lancaster.

Repair of the city's signals is the responsibility of the county until the next fiscal year, when the city will step in. All signal-timing changes will be coordinated with the county until then as well.

At the intersections where cameras have been mounted, computers track the motion of cars and trucks through a complicated motion-detection system that even accounts for blowing winds and vehicle shadows.

The detection system lets the computers "read" the traffic flow and make the adjustments that allow workers driving to U.S. Air Force Plant 42 to get there faster on weekday mornings and shoppers headed for the AV Mall to get there more safely on weekends.

Most drivers seem to want to know why they can't get a series of green lights whenever they hit a major roadway, Horne said. The answer is because traffic patterns change throughout the day, the week, the season and the year.

Giving one or two cars consistently green lights while dozens of vehicles are lining up on adjoining streets would not be the most efficient way to help motorists reach destinations, he said.

All drivers headed in the opposite direction of those getting the green lights probably are getting red ones, he said.

In addition, traffic engineers have to way to make sure all the drivers ahead of a target driver clear the way before the target driver reaches the next intersection, he added.

"In some cities that are really congested, timing a signal so a guy gets a green here, and so many seconds later gets a green there, is worthless because he can't get there" due to other traffic, Horne said. "You actually may have to make a more distant signal green ... because you want the queue to get out of the way so this guy has a place to go."

"Depending on the volumes you've got to deal with, the spacing of the signals, whether you have left-turn phases - all of those things come into play" when trying to adjust traffic signals, Horne said.

"If most people knew what traffic engineers know about traffic signals, they wouldn't ask for them as often," he said, chuckling again.

In the future, the city might add the ability to ticket motorists via on-screen violations, Horne said, noting that cities with such systems typically reduce right-turn-on-red collisions about 40%.

Ticketing is not possible with the current system, he said. Upgrading it would cost as much or more than the revenue it would generate, but it would add to driver safety and savings.

"If I have a signal with 20,000 or 30,000 cars a day traveling both streets, if you save just one second of time per car in fuel and pollution and time - add that up over one year," Horne said. "Multiply that times the number of intersections we've got and you see why we want to spend time keeping them timed."

"Our goal is not to have to ticket anybody," he said. "We'd rather have them driving safely."

Tickets cost as much or more to issue than they generate in revenue, Horne said. "The point (of ticketing) is to reduce the accidents and the delays, because those costs far outweigh what little we get back.

"Having somebody injured for life - how many tickets are you going to give out to make up for that?" he said. "You want to give out that ticket beforehand to improve driver behavior so that doesn't happen."