The crash was reported about 3:55 p.m. on the westbound 91, just west of Arlington Avenue, near downtown Riverside, according to the California Highway Patrol.
According to the agency, the three vehicles impacted in the fast lane, though details were scarce.
Riverside Fire Department personnel reached the location within a few minutes and found the motorists outside their vehicles, uninjured, according to officials at the scene.
CHP officers blocked two of four lanes for first responders, and a SigAlert was issued just after 4 p.m. due to the ensuing traffic jam in the middle of afternoon rush hour.
One of the cars, a Honda sedan, sustained major damage and had to be towed away, according to the CHP. The other vehicles apparently remained drivable.
The SigAlert was lifted at 4:30 p.m., after the fire engines cleared and the damaged vehicles were moved to the shoulder of the freeway.
The cause of the collision was under investigation.