Nissan Micra - the driving school favourite, hence chosen by many timid drivers as their first car (which presumably is why Nissan offer driving schools such generous terms). Nervous driver = accident prone
Small white vans - driven by young wannabee jack-the-lads who feel they don't look 'cool' in a small van. Disgruntled driver = accident prone
BMW - because they're BMW drivers - 'nuff said

This could so easily turn into "Vent your prejudices" couldn't it?