Caltrans workers blocked lanes on I-8 near College Boulevard due to a large sinkhole that opened on the shoulder. Photo by Chris Stone
Caltrans workers blocked lanes on I-8 near College Boulevard due to a large sinkhole that opened on the shoulder. Photo by Chris Stone

Caltrans workers Thursday were investigating the cause of a 30- by 20-foot sinkhole (20 feet deep) on the shoulder of Interstate 8 near College Boulevard that closed several eastbound lanes.

Two of the five lanes will remain closed Thursday evening as Caltrans workers work around the clock to repair the road before the Friday afternoon commute, said Ed Cartagena, spokesman for Caltrans.

The eastbound ramp from Warning Road also will be closed Thursday night. Traffic was backed up to at least Interstate 15 Thursday afternoon.

The erosion revealed an inactive pipeline that irrigated roadside landscaping until about 10 years ago, but it was unclear if the defunct water line had anything to do with the problem, Cartagena told City News Service.

Caltrans advises motorists to take alternate routes Thursday evening. Long delays are expected, Cartagena said. The Metropolitan Transit System says it will offer overnight parking at Qualcomm Stadium to avoid severe traffic congestion.

“There are more than 5,000 free parking spots available at Qualcomm for trolley passengers,” said MTS. The stadium is served by the Green Line and has connections to other lines in La Mesa, El Cajon and downtown San Diego.

Motorists are asked to park under or adjacent to the Qualcomm trolley station, on the south side of the stadium. Traffic to the stadium is closed between 1 and 4 a.m.

At 4 p.m., I-8 eastbound was backed up to state Route 163.

About 10:15 a.m. the California Highway Patrol put out an alert of the problem and by 11:11 a.m. a SIG alert was called.

Initially, three lanes closest to the sinkhole near San Diego State University were closed, but by 1 p.m. only two lanes were blocked, according to Caltrans on Twitter. An irrigation pipe was exposed.

The cause of the sinkhole was under investigation, and lanes were closed because the soil under the lanes hadn’t been checked. Photo by Chris Stone
Caltrans workers blocked lanes on I-8 near College Boulevard due to a large sinkhole that opened on the shoulder. Photo by Chris Stone
Eastbound I-8 traffic was backed up for miles to I-15. Photo by Chris Stone