I can guess a few reasons: * Cars tend to be bigger i.e. more dangerous in the US * Drink driving seems to be more acceptable in the USA. * The driving test

I can guess a few reasons: * Cars tend to be bigger i.e. more dangerous in the US * Drink driving seems to be more acceptable in the USA. * The driving test in the UK is much tougher than even the toughest us state * Most of the US don't have mandatory annual vehicle inspections to check they're safe and roadworthy