A Sonoma County man who was trapped inside a burning motor home that may have exploded east of Petaluma died Sunday morning, the fourth fatality on North Bay roadways in two days, authorities said.

Police said they received multiple 911 calls shortly before 8 a.m. Sunday from passersby who had stopped to help along Highway 116 and said they could hear a person inside the burning vehicle, which had crashed after catching fire.

At least 10 emergency vehicles responded to the scene, including firefighters from Schell-Vista Fire Protection District, Cal Fire and the Sonoma Fire Department.

The man, whose name was not released, was not able to escape, the CHP said.

“Witnesses did report hearing someone inside the vehicle; however, they were unable to get to that individual due to the flames,” said Anna Paulson, a CHP spokeswoman. “The fire completely engulfed the motor home.”

The man was driving eastbound on Highway 116, also known as Stage Gulch Road, when he crashed into a grassy, wooded hillside near the intersection with Adobe Road. The fire appears to have ignited before the crash.

The motor home left black skid marks on the roadway for about 250 feet leading up to the crash site, along with a trail of debris.

Among the debris was a door and a window, which appear to have been blown off by an explosion, authorities said. The door was lying on the side of the road leading up to the crash site, and the window was about 30 feet up the hill in the grass.

The cause of the fire is under investigation, the CHP said.

“You can see that there are skid marks, and a large amount of debris all of a sudden,” Paulson said. “We’re still investigating.”

Paulson said she could not release the driver’s name until his family members are notified. Other details, including the year and model of the motor home, were not available.

“It could have been a mechanical issue, but we won’t know until we finish our investigation,” Paulson said.

The crash backed up traffic on Highway 116 for hours Sunday morning as motorists were rerouted. The roadway was cleared by mid-morning, but a heavy stench of smoke lingered in the air.

Three others died in collisions in the North Bay on Friday night.

An 86-year-old Napa County man identified as Shirley Benson died Friday in a crash at about 5 p.m. near St. Helena that also injured his wife. Shortly after, a man and his passenger were killed in a three-car collision on Highway 101 near Geyserville. Authorities have not released their names.

A Cloverdale father and daughter injured in that crash, Richard Anderson, 50, and his daughter, Abby, 18, remained in critical condition at Santa Rosa Memorial Hospital Sunday, according to Vanessa DeGier, a hospital spokeswoman.

Authorities are still interviewing witnesses in Sunday’s motor home fire and have asked anyone who saw the crash call the CHP at 253-4906.

You can reach Staff Writer Angela Hart at 526-8503 or angela.hart@pressdemocrat.com.