This is a great concept and I like how it's both simple and fun - that's a rare combination in games. In terms of quarrels, I'm not sure if the intention was to encourage the player to let the AI kill each other, but that's certainly the case - I found that crashing into people rarely helped me and would result in a ganging-up, so my main strategy was to drive around and let them hit each other. I think it could do with a bit more 'juice', although it's definetely not lacking in terms of music or gameplay.