Dod101 wrote:it is the lane hogger that is wrong not the undertaker. I do not though want a careless driving conviction, although I would not see it as careless driving. In fact any undertaker is likely to be a very careful driver, alert to the possibility of the lane hogger suddenly changing his mind.
Yes, the rule about undertaking is arbitrary and seemingly not founded on a safety issue at all. I feel the same way with the law against jaywalking in the US, because in the UK there is no such prohibition. If some countries have a law and others do not, then the chances are that it is not an important law.
The one safety concern that can happen with undertaking is if you move to the left lane to undertake someone in lane two, whilst someone is overtaking that same vehicle in the fast lane. Then both passing vehicles try to re-converge into the middle lane at the same time. I've seen that nearly happen, but it should not if both drivers maintain awareness. Americans manage it all the time.
Dod101 wrote:As for the speed limit, I have always thought that if the limit is 70 mph it should mean that. Why on earth they allow another 10% plus 2 mph I have no idea. Take away the plus 10% and leave it as plus 2 mph would make sense to me to allow for slight variations in readings.
I believe the reason is pragmatic. Car speedometers may only be accurate to within 10% or so. And even the police measuring kit has a margin of error. So in practice to get a ticket in a 70 zone means you are doing 80 or more, which translates into a de facto 80 limit.