OAKLAND — A dump truck driver lost control of his vehicle Wednesday during rush hour traffic while exiting Interstate 580 in Oakland, and set off a chain reaction of accidents that involved 13 cars and injured four people sending them to local hospitals, police said.

The rush-hour accident occurred where eastbound Grand Avenue off-ramp meets MacArthur Boulevard, near Lake Merritt. The off-ramp was shut down by 5 p.m., shortly after the accident, and remained closed several hours later, according to the California Highway Patrol.

Oakland Police  diverted traffic around Grand and Lake Park avenues to keep cars and people out of the area while investigators studied the accident scene, said Oakland police Officer Holly Joshi.

It was unclear how serious the injuries were for the victims who were taken to hospitals, Joshi said.

Early reports were that the dump truck driver said his brakes failed while he was exiting the highway, according to the CHP.

If you or a loved one has been injured in an auto accident call 888.777.1776 or email us to speak with a personal injury lawyer at Alexander Law Group, LLP, LLP. All calls are free and confidential.