Desmond Anderson San Diego County
Supervisor Jim Desmond and public works officials look over a new backup battery system. Photo credit: County News Center

Officials flipped the switch on a new traffic light backup system in San Dieguito that could make residents around the county safer during emergencies.

The pilot project, located at a traffic light at San Dieguito Road and Via Dos Valles, was chosen at an intersection that county Supervisor Jim Desmond’s office called a major evacuation route for several communities.

They include 4S Ranch, Carmel Valley and Rancho Bernardo.

The project replaced the traffic signal’s existing lead, acid-based backup battery – the kind in many cars – that could keep the light operating for four to six hours in a blackout, to newer nickel-zinc batteries.

The replacements can keep the lights working for more than 24 hours.

Having extended backup power could keep people from racing through non-working traffic signals and potentially save lives in an emergency evacuation or when San Diego Gas & Electric institutes a power shutoff in high-wind conditions.

“We can’t stop wildfires from occurring in San Diego County, but we can do our best to keep people safe,” Desmond said. “Seeing this backup battery’s capabilities, I’m confident this will be a major asset during Power Safety Power Shutoff events, and I look forward to seeing many more installed throughout the county.”

The San Diego County Board of Supervisors, prompted by Desmond and Supervisor Joel Anderson, called in March to look for ways to reduce the potential impacts of the shutoffs, including backup power at major intersections.

“Installing these longer-lasting emergency backup batteries at traffic lights, particularly along evacuation routes, is something that will be very important for the safety of my constituents,” Anderson said. “My constituents have lived through major wildfires in the past, including two of the largest in state history, the Cedar fire in 2003 and the Witch Creek fire in 2007.”

County public works officials said the department expects to eventually install the extended backup batteries at roughly 200 traffic lights operated on county-maintained roads in unincorporated areas.

The San Dieguito light will serve as a test site because it has ample space for installing up to eight nickel-zinc battery packs. The vendor paid for the project because the installation is part of a pilot project.

The department first installed lead-based backup batteries in traffic lights on county-maintained roads after the widespread Southwest blackout in September 2011.

The blackout, the largest in California history, suddenly cut power to 2.7 million customers for more than 11 hours, including all of San Diego County, parts of Mexico and Arizona, southern Orange County, Imperial Valley, Mexicali Valley and Coachella Valley.

In addition to closing schools and businesses, suspending water service in some areas and shutting off television and radio news, the blackout also and shut off traffic lights, snarling traffic.

County officials who had already seen the traffic jam impacts of the 2003 and 2007 wildfires here recognized the potential for problems in emergencies.

The likelihood of traffic lights being shut off has increased in recent years after utilities started shutting down power to temporarily cut electricity in areas during “red flag” high-wind events. The action prevents downed lines from sparking fires.

In their March 2 letter, Desmond and Anderson said such power shutoffs affected 66 communities in 2019, including in San Diego and Native American reservations.

In 2020, the shutoffs affected 44 communities, including seven cities and reservations.

– City News Service