It wasn't clear what caused the landslide that pocked the coastal highway with holes, including one more than 40 feet deep and 200 feet long, CNN reported Sunday.
A cement truck was stuck when the ground began to shift but the driver escaped before the truck fell into the Pacific Ocean to the west of the road, the report said.
Officials say it may take as long as a year to repair the damage and building a temporary road is among the options under consideration.
For now, motorists are using a nearby free road, CNN said.
The damage occurred about 60 miles from the U.S.-Mexico border.
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