In the UK there is no legal tolerance for going over the speed limit to overtake or merge. The only defence (and not even technically a defence) is that there w

In the UK there is no legal tolerance for going over the speed limit to overtake or merge. The only defence (and not even technically a defence) is that there was some emergency/duress. Some police might individually tolerate it, but it won't get you out of a fine and you'd almost certainly immediately fail your test. I'm actually kind of shocked to read that a (presumably European?) country would tolerate going 30kph over the limit on a driving test! However, the UK is fairly strict about traffic rules. You can't even go through a red light to let an ambulance through here. People have been fined for it, and their fines have been upheld at appeal. Personally, I would imagine it's very unlikely to improve safety, and have seen near crashes result from it, so I think if you're needing to go 30 kph over the limit to make the overtake, then you probably should have just waited. However, I am completely willing to accept that this is a case where evidence should outweigh anecdotes, so if there was some study and reliable data to show that this sort of a tolerance is a good idea, then we should absolutely adopt it into the law under some objective criteria. I do of course agree about malicious enforcement though. Again that's something that doesn't tend to be a big problem in the UK. Speed limits must be posted on both sides of the road to be enforceable, and if it's not the default limit (e.g. 30 in a built up area), there will be repeater signs every 200 metres or so. Plus we tend to also paint the limits on the road, and speed cameras are painted yellow and have a sign telling you that there are cameras, often with a reminder of the limit. You do occasionally get situations where the signs are obscured by trees, especially now that maintenance budgets have been cut, but you can use that to get out of the fine. My experience driving around the UK is that it's really rare that I don't know what the limit is, and if I don't, 99% of the time it's my fault for not paying attention.