California - Involved in accident caused by prank (very loud) train horn on another car. I'd like to fight the ticket I am guessing I am going to get, and likely future lawsuit.

California

Using a throwaway

This happened yesterday

Driving down a 3 lane road, I am in the middle lane, light a head of us abut 1/4 mile up turns red, everyone starts slowing down, but still moving ~30MPH, douchebag in a ridiculous lifted truck to the right of me as a "prank" honks his horn. Not any horn, but a fucking train horn.

Scared the shit out of me

Here is what happened:

• Horn goes off, it caused me to swerve and slam into the back of the car in front of me in the next lane over
• Another car was hit by the car I hit
• We are all in agreement that we do not know if he hit the car first or if I pushed him into the car because he was equally scared and he slammed his brakes and left his lane when he heard the horn.
• Shockingly enough, the truck stuck around
• MS Paint diagram of the situation - https://i.imgur.com/G4NY5HC.png

No tickets were handed out to those of us in the accident as the cops wanted to take their time concluding their investigation, but we were all told that tickets are coming. The guy in the truck did get a ticket for having using his train horn as that's illegal

My main question here...Am I at fault here? What can I do to pin the cause of this on the guy in the truck with the super loud horn? Some quick googling says that his modification is be illegal (as evidenced by the ticket he received), but are his actions enough to make him at fault?

Written By: ItchyGap
Source: http://bit.ly/2DgmUxK