There was an Uber driver in from of my son at a red light. When the light turned green the driver started to go and then abruptly slammed on the brakes and my son hit him. Didn't damage the Uber car but lots of damage to my son's car. The Uber passenger said at the scene she had no idea why he suddenly hit the brakes. I think the Uber driver is at fault because hitting the brakes for no reason is erratic driving. No police involvement, but they exchanged information. Opinions?