A Bay Area politician demanded answers from state authorities Friday after a surprise construction impact along Highway 1 has snarled traffic for days, with possibly terrible effects through this coming holiday weekend. 

Half Moon Bay residents have seen “complete gridlock” after a Caltrans repaving project modified traffic signal patterns, forcing long waits at the lights, according to San Mateo County Supervisor Ray Mueller.

“I’m furious,” Mueller said in a Friday news release. “Residents and local businesses deserve answers about why this work is occurring immediately before one of the busiest weekends of the year for the Coastside. Caltrans needs to fix this now – today, immediately.”

Mueller told SFGATE by phone that sheriff’s deputies are attempting to direct traffic, but called for more action before crowds descend on the scenic byway for the holiday weekend. He said his office was not given notice about the impact.

Caltrans spokesperson Jeneane Crawford said in an email to SFGATE Friday that three traffic signals at Highway 1 and Capistrano Street, Coronado Street and Russeau Francais Street have been set to scheduled timing because a repaving project has currently made the traffic detector hardware installed under the pavement inoperative. 

“The timing is being actively monitored and adjusted to alleviate traffic back-ups to the extent possible. All other intersections along the project corridor have fully operational detector loops,” Crawford said in an email.

Crawford said Caltrans “is working to lessen the impact” and will halt nighttime construction work on the project throughout the holiday weekend, but she did not say if the traffic signals could be changed immediately.

Half Moon Bay is roughly 25 miles south of San Francisco on Highway 1 and has miles of beaches that are often packed during summer months. The California State Parks Foundation recently named Half Moon Bay State Beach the best state park for beaches. The route is also popular for road-trippers driving the coastal highway between San Francisco and Santa Cruz.

David Cosgrave, a senior legislative aide for Mueller, said the traffic signals are creating long delays for drivers on the busy highway even when there’s no one waiting on the side street. 

“The lights have a lengthy delay even if no cars or pedestrians are there,” Cosgrave told SFGATE by phone. “That stops traffic on Highway 1, which is the only artery on the coast, and it’s been causing major backups and delays and impacts the coastal residents.”

Cosgrave said he’s heard from constituents who have had to sit in traffic for nearly two hours this week because of the traffic signals. He said Highway 92, which connects Half Moon Bay with Interstate 280, is not being affected by the problem.