The hole opened up on southbound Highway 87 near West Virginia Street in San Jose early Thursday morning. Crews say recent rain may be to blame.
Caltrans began re-opening two southbound lanes around 4 p.m. that had been closed all day for the repair. Maintenance crews discovered a sinkhole early Thursday morning that the CHP described as a 30-foot by 30-foot hole.
An extremely wet rainy season and a high water table in San Jose created the problem, according to Caltrans.
The hole was dug up, then filled with a mixture of quick-drying concrete and asphalt.
"We anticipate there's going to be a second phase as necessary to fix this permanently so it doesn't happen again, and that will involve replacing concrete slabs as well as upgrading the drainage system underneath the roadway," said Bernard Walik with Caltrans.
Walik said if a second phase is necessary, there will likely be road and ramp closures in the affected area, but Caltrans anticipates traffic will continue to flow on both sides of the freeway.
Traffic was light while Caltrans worked to repair the sinkhole on Thursday.