LOS ANGELES - The rescue was described as almost miraculous. A family of four whose car had careened off a treacherous cliff-top road in Northern California, plummeted more than 250 feet (76m) and trapped them on Monday managed to survive and avoid life-threatening injuries.

But now, authorities say that their car’s dramatic drop wasn’t an accident, but an “intentional act,” and that the father could face charges.

Mr Dharmesh Patel, 41, of Pasadena, California, was arrested late Monday on suspicion of attempted murder and child abuse, the California Highway Patrol, Golden Gate Division said Tuesday afternoon.

He will be transported to San Mateo County Jail after being released from the hospital, authorities said. The San Mateo County district attorney said that it had not received the case from the Highway Patrol to determine whether Mr Patel should be charged.

The investigation into the crash involved numerous emergency responders and officers and required the use of a helicopter to extract the family from their mangled white Tesla.

Just before 11am Monday, officers were called to help with the rescue, which was on a scenic stretch of Highway 1, about 20 miles south-west of San Francisco.

The area where the car fell is very high and filled with rocky cliffs that drop down to the Pacific Ocean and beach area, Mr Brian Pottenger, the battalion chief of the Coastside Fire Protection District’s San Mateo-Santa Cruz unit, said in an email.

It is known for being difficult to drive through, and is often referred to as Devil’s Slide. Mr Pottenger said the vehicle landed upright, on its wheels, which made the passengers easier to access through the side windows.

“It is very unusual for anyone to survive an accident of this magnitude in this area,” Mr Pottenger said.

Mr Patel’s wife, 41, and their two children, a 7-year-old girl and a 4-year-old boy, were trapped in the vehicle when emergency responders arrived, Mr Pottenger said.

Firefighters extricated the victims and, using ropes, brought the children to the road on stretchers and then to a nearby hospital. The children were uninjured, authorities said.

The adults, who suffered non-life-threatening injuries, were hoisted onto a helicopter and taken to the highway, where they were transferred to a hospital by air ambulance.

The highway patrol said in a news release Tuesday afternoon that investigators had worked overnight Monday, interviewing witnesses and analysing the crash site, and had determined that it had been “an intentional act.”

Authorities said it was unclear if the Tesla was in a self-drive mode, although the agency said it did not believe that was a “contributing factor.”

A highway patrol spokesperson declined to specify what evidence had led authorities to arrest Mr Patel, saying only that they felt the proposed charges were “justified.”

The stretch of highway where the accident took place has been the scene of dozens of fatal accidents in recent decades in which people have driven off the road.

In 2013, a tunnel opened that was designed to make the road safer. Even so, at least nine fatalities have occurred there since, The San Francisco Chronicle reported last year. Monday’s crash occurred just south of the tunnel.

A report published in 2021 by the California Department of Transportation said that run-off-the-road accidents were more common in the area that includes Devil’s Slide than elsewhere in the state because of edge of pavement condition, steep drop-offs and a lack of permanent barriers. Landslides in the area have also caused periodic road closures. NYTIMES