Back in the late sixties my dad killed an old boy who came out of a side road on his bike, over the limit on alcohol, half blind, half deaf, no lights, dodgy brakes and his family had warned him repeatedly about riding home from the pub in the dark. He came through the windscreen and died in my parents' laps. They were both medical so they weren't as traumatised as their passenger. The Police came and examined my dad's car in minute detail. filling in a thick questionnaire about the condition of the car, tyre treads, brakes, were the windows clean, wipers, lights, was the heater on - could have made him drowsy, did the floor mats impede the brake pedal and so on. Luckily the car was in perfect condition, otherwise he'd have been prosecuted for manslaughter. When they measured the skid marks they put it to him that he must have been exceeding the limit; he admitted that he had been. However the case was for them so cut and dry that the copper just said "Let's say thirty then, shall we?" and that was the end of it. Maybe the fact that my Dad was the village doctor helped, I wonder if he would get away with it nowadays?
For the rest of his life my Dad used to flinch whenever a car or bike came up towards a side junction. What I learned was always to keep the car in perfect order and clean and well maintained - even my rusty old Land Rover always had perfect brakes, tyres etc and never failed an MOT in the 10 years I had it.