Lanes of westbound state Route 76 were blocked Monday evening near North River Road in Bonsall due to an RV fire, authorities said.
The vehicle fire broke out a little after 5 p.m., North County Fire Capt. John Choi said.
Responding firefighters arrived at the scene to find the RV fully engulfed in flames, Choi said.
It took crews about 15 minutes to get the blaze under control.
At least one person was still in the vehicle when the fire was first reported, according to a California Highway Patrol incident log, but Choi said no one was injured.
The American Red Cross was called in to find shelter for the two people who were staying in the RV, Choi said.
Initially, both lanes of westbound Route 76 were blocked, but one was reopened around 6 p.m., according to the CHP.
North County Fire tweeted around 7:40 p.m. that all lanes were again open.