I was making right turn on a red light with a dealer loaner (evoque), waited for few seconds, there's no car on the lane I was gonna turn into. The moment I turn into that lane, a civic supposed on the left lane merge to the right lane slam on the brake. The hit was pretty light, only scratch on both bumper, some plastic trim loose. I was in rush, so i didnt call police, She took a pic of my Loaner paper(she didn't ask my insurance or driver license, weird) . I did took a pic of her driver license and her insurance card and the damage to her bumper. I don't know who's at fault, but there's one witness( a tourist from Seatle) said she slammed the brake, there's no car in front of her. What do u guys think who's at fault? and how am I gonna deal with this kind of situation? I will probably go to my dealer at San Francisco tomorrow see what to do. I don't even have my insurance paper with me.