Bridge’s Laser Warning System Takes Safety to New Heights

“Star Wars” hits the road next week when a laser system begins warning workers and drivers of a looming low bridge, state transit officials said.

The laser system will alert drivers and California Department of Transportation workers when a vehicle over 14 1/2-feet tall approaches the Emerald Drive bridge over California 78 in Vista, said Kyle Nelson, a Caltrans spokesman.

Installation of the laser system begins Thursday night near the two-lane bridge. The bridge usually hangs 16 1/2 feet above the highway, but will have a lower clearance while workers add four lanes to the bridge.

Bridges under construction are lower because of the wooden framing, called falsework, that is placed beneath it, Nelson said. The falsework will eventually have concrete poured into it, he said. Once the concrete sets, the falsework is removed and the bridge is at normal height, Nelson explained.

Eddie Ybarra of Select Electric Inc., installer of the system, said a sign will alert drivers of the system well before they reach the beams.

“When trucks taller than the bridge pass laser beams roughly 1,000 feet from it, flashing lights and sirens are set off,” Ybarra said.

The lights and sirens are part of what Nelson calls a “dual alarm system.”

“First, an alarm will sound on the work site. Workers can scatter and escape the path” of an oncoming vehicle, Nelson said.

“Second, a set of flashing lights and a flashing message sign will hopefully attract the attention of a truck driver to take an exit route.”

Vehicles have a single exit before the bridge, and can rejoin highway traffic once they pass the bridge, Nelson said.

In the event of a collision, “a lot of the falsework would tend to come down,” said Arnie Gerfen, an electrical engineer with Caltrans. “It could cause all kinds of grief.”

A year ago, a crane that was too tall drove into a Del Mar Heights bridge construction job, killing the driver.

“The safety of the workmen and the safety of the traveling public is the priority with this” system, Gerfen said.

The laser warning system is the first of its type in the county.