I was a participant in a very similar incident, except that I was the cop who took the cyclist to jail. A cyclist in his late 30s was almost hit by a 50-ish driver in a BMW. Road rage ensued between the two...words exchanged, fingers flipped, etc. The driver parked at his destination and the cylcist caught up to him. The cyclist pounded on the window of the BMW and threatened to harm him. When I arrived on the call and got the stories straightened out, I had to arrest the cylcyst for criminal threats (section 422 of the California Penal Code). I did not cite the driver.