Raleigh wrote:
it goes back to days of weaponry, and jousting, and most people being right-handed.
So, tradition.
Well, I think "most people are right handed" would be an argument against that, because in most states you drive on the right lane and only sometimes have to deviate leftwards... that just might be an easier orientation for right handed people. Since Driving everywhere basically gives an edge to the right side it's more natural to drive on the lane of the hand which you hold your pencil with.
But yeah, I guess old habits die hard. If I was British I'd never get used to driving anywhere else