Two adults, a four-year-old girl and nine-year-old boy were trapped in the vehicle for an hour before being removed by rescue crews who then towed the electric vehicle up to the roadway, according to California Highway Patrol.
All of the people in the vehicle were taken to area hospitals.
The accident on Highway 1 in San Mateo County took place just before 11am on Monday, according to the California Highway Patrol and Cal Fire.
Following an initial investigation, the CHP does not believe the Tesla was operating in Autopilot or Full Self-Driving mode at the time of the crash, Officer Mark Andrews said.
The cause of the crash is still under investigation, but Mr Andrews said road conditions are not believed to have been a factor. He added that there was no guardrail at the spot where the car went over the cliff.
“The car traveled off the main portion of the roadway. For what reason, we don’t know,” he said.
Devil’s Slide, a steep, rocky and windy coastal area about 15 miles south of San Francisco, is known for fatal car wrecks.
“We go there all the time for cars over the cliff and they never live. This was an absolute miracle,” Brian Pottenger, a battalion chief for Coastside Fire Protection District/Cal Fire, told the Associated Press.
Witness Robin Johnson gave NBC Bay Area details about what had happened.
“As I’m driving by, I’m like, ‘Wow, he’s driving extremely fast to take that exit. You’re not even supposed to be going up that way,” she said.
“And I can see in my rear-view mirror this car that just go over the edge and straight down.”
Authorities have not yet said what caused the vehicle to leave the road and careen down the cliff and an investigation is underway.
“We come out here, unfortunately, for things like this. And this was nothing short of a miracle that they survived,” said Brian Pottenger, a battalion chief with the Coastside Fire Protection District, told KTVU.
And he added: “We did have one witness state the vehicle did veer off the road to the right-hand side, went up into the dirt area, and then proceeded to go off the cliff.”