Four individuals were transported to San Luis Obispo-area hospitals after two cars collided on South Higuera Street near San Luis Obispo creek bridge.
California Highway Patrol said they believe alcohol was a factor in the crash.
According to officials, a black BMW was traveling north on South Higuera when it crossed over the center line, striking a turquoise Chevy Equinox in an off-center head-on crash. The collision forced the Chevy onto the bridge railing.
All four individuals were transported to area hospitals.
The accident took place in Cal Fire jurisdiction, but they requested assistance from SLO City Fire. Two engines, including a ladder truck, were dispatched from SLO City Fire.
All units cleared the scene by 11:18 p.m.