Highway 92 in San Mateo County continues to be shut down in both directions and authorities early Friday had no estimated time lanes would reopen.
The county sent an alert at about 3:30 a.m. Thursday indicating the closure from upper Skyline Boulevard to Pilarcitos Creek Road. It did not initially specify a reason for the complete closure but later said the hazard was classified as a sinkhole.
Motorists were urged to take alternate routes. Caltrans recommended drivers take Highway 1 via Pacifica to get to and from Half Moon Bay. There is another sinkhole on Highway 1 at Pescadero that has traffic down to one lane in that area.
Get a weekly recap of the latest San Francisco Bay Area housing news. Sign up for NBC Bay Area’s Housing Deconstructed newsletter.
On Wednesday, the two-way highway was closed for hours because of potentially hazardous conditions, specifically the possibility of a sinkhole forming in the westbound lane, the California Highway Patrol said. Later in the day, the eastbound lane was reopened and was used for two-way traffic control.
The highway is a major route for travelers between the county's Bayside and Coastside regions.
