A motorcyclist who saw a Mercedes weave and smash into several cars in Colton then flee the scene followed the driver on a chase, helping police track him down.
His effort helped police find the hit-and-run driver who was later arrested on suspicion of DUI.
The motorcyclist, who goes on You Tube by the name Dick Danger, recorded the crashes and the chase on video.
The video shows a black Mercedes sedan moving fast on a surface street on the wrong side of the yellow line, sideswiping a car heading in the other direction that just managed to swerve on time.
It then clips the back of a pickup truck and smashes into a Toyota Prius stopped at a light, crumpling the front section of the Mercedes and leaving debris on the roadway.
The driver of one of the struck cars then confronts the man, who drives off from the scene despite the smashed-in front end.
Dick Danger promptly runs back to his motorcycle and gives chase, staying on the phone with 911 to give location information to officers.