at this stage, you are being told that the police are considering a complaint that has been received. They have to give you that notice within 14 days, before they even consider whether there is a case in it, and probably before they have had a chance to interview the complainant. When they do so, it is likely that they will withdraw the notice. It is possible, however, that injury occurred to someone in his car during a manoeuvre to avoid you, or a collision may have occurred with another vehicle. This would be classed as an accident even though you were not involved in any collision. For the moment, I suggest that you make some notes of exactly what happened, speeds, direction of travel, weather etc. Incidentally, if there was an accident, the other driver is required to stop as well as you. You have a defence in that you were not aware that an accident occurred. He does not seem to have that defence.