A 4-foot-deep sinkhole was discovered Wednesday along southbound Highway 1 near Morro Bay at the South Bay Boulevard exit.
The sinkhole, which was not causing any lane closures, resulted from a broken drainage pipe that caused water to impact the pavement, Caltrans spokeswoman Susana Cruz said.
Caltrans also was keeping an eye on the southbound South Bay Boulevard off-ramp because some water had started to develop underneath the road, Cruz said.
The sinkhole is 12 feet in diameter, Cruz said. Crews have put a metal sheet over the sinkhole, and Caltrans is in the process of lining up a contractor to make emergency repairs.