Work Begins on TV Traffic Monitor System for Coronado Bridge

Work on the long-awaited television traffic-monitoring system on the Coronado Bridge began this week with the laying of conduits for the highly specialized system, state transportation officials said.

Despite technical concerns and problems with a bidder, the system is expected to be completed in June, they said.

The $977,000 system, consisting of five cameras and four electronic message signs, was approved by the California Transportation Commission in October, 1985, but a contract was not awarded until August.

“The wheels of progress grind very slowly,” said Ray Granstedt, Caltrans regional traffic system chief. The long lapse between approval and the awarding of a contract was due in part to the research involved in designing the system, he said.

“The cameras and signs are highly specialized items and can’t be bought off the shelf,” Granstedt said. “We’re still at the learning stage.”

The Coronado Bridge system will use TV cameras that will feed pictures back to a central information center at the toll plaza. If an accident occurs on the 11,000-foot-long bridge spanning San Diego Bay, operators will be able to warn motorists by flashing one of 16 pre-programmed messages on the signs.

Although the idea of using TV cameras to monitor traffic is not new--Los Angeles has been using them on the Santa Monica freeway for some time--the Coronado system has different design requirements, Granstedt said.

“There are . . . different conditions on a bridge,” he said, such as mounting requirements. “The only plausible place for them (on the bridge) is along the (light poles). When the winds are blowing, there’s a lot of vibration on a pole. When you mount a camera on it, it’s difficult to get a very clear picture.”

Other factors affecting cameras on the bridge are rain and fog. “When there is heavy rain and there is a fair amount of traffic, a lot of spray is kicked up, so it’s almost like a fog,” Granstedt said. In fog, cameras can see almost nothing. “There are certain limitations to video,” he said.

The use of cameras on a bridge is different than on a freeway, echoed Dixon Yeazell, a transportation engineer at Caltrans’ San Francisco office. Cameras on the freeway monitor the shoulder, but those on a bridge are aimed into the traffic.

“They have to see across the (headlights), to see if people are walking around,” he said. “Most (conventional TV) cameras would want to close the iris, to start squinting, and they can’t see details that may be critical to getting the right kind of aid to an accident on a bridge.”

Yeazell said that the cameras used on the Coronado Bridge are not unlike the ones that will be mounted along the Bay Bridge connecting San Francisco to the East Bay. That project, estimated to cost $5 million, has already been started. Cameras will be in place along the upper deck of the bridge by June, but the entire system will not be completed for three more years.

Aside from technical considerations, the Transportation Commission was late in awarding a contract for the Coronado Bridge because the lowest bidder had a licensing problem. According to Jim Larsen, Caltrans public information officer in San Diego, bidding started on July 17. “Usually a contract is awarded one month after the bidding starts,” he said.

Two companies bid for the contract, according to Russ Lightcap, the office engineer who reviewed the bids for Caltrans. However, the lowest bidder ($810,140), Perry Electric of Spring Valley, was rejected because it did not have all the necessary licenses to do the work.

The second-lowest bidder ($925,686), McCain Construction Co. of Encinitas, was awarded the contract on Aug. 21, although Lightcap said Caltrans engineers have estimated that the job could be done for $880,000. The budget for the project now, including contingencies, stands at $977,000, according to Lightcap. Each camera costs $5,730 and each sign $19,600.

The need for a traffic monitoring system on the bridge is critical, Granstedt said. Traffic has increased 7% between 1985 and 1986, and accidents have risen proportionately.

“We’re not increasing the capacity of the bridge (by using the system),”he said. “But we’re hoping to cut down the response time in reacting to an incident on the bridge and ensure that traffic moves consistently across the bridge.”