OCEANSIDE, Calif. — A bicyclist was fatally struck by a vehicle in North County on Tuesday, authorities said.

The Oceanside Police Department announced at 5:19 p.m. that all southbound lanes of Douglas Drive were shut down from El Camino Real to Mission Avenue due to a traffic accident.

Several hours later, the department tweeted that the lanes had been reopened following a fatal traffic collision. According to police, a preliminary investigation indicated that a bicyclist traveling on Douglas Drive, on or near the sidewalk, was struck by a motorist.

Authorities say the male adult bicyclist is believed to be in his 50s. He was reported to have succumbed to his injuries at the scene. His identity has not yet been released.

The department said the motorist remained at the scene of the crash and was arrested for suspicion of driving while under the influence and vehicular manslaughter.

Anyone with information about the collision is encouraged to call Crime Stoppers at (619) 235-8477.