Agreed. The problem is that 'tiredness' is not quantifiable in the same way as drink driving is and can be pernicious in that you may start off feeling fine when you start your journey up the M6, but the monotony can start to affect concentration and so on. There are laws that can be used - driving without due care and attention for example, but quite often this only happens after an accident has happened.
Yes, I agree. If there was a way to quantify tiredness using an electronic device as there is to quantify blood/breath alcohol levels, I'm certain there would be a limit.
As I mentioned tachographs do go some way towards solving this, but they only work for people whose main task is driving, as they don't stop you, for instance, going out on the lash on Friday until 4am, getting up at 6am, spending the day doing heavy digging work in the garden to clear off the hangover then driving 200 miles at 10pm, because there is no realistic way for them to take into account those other activities despite the fact that someone who has done the above will not be fit to drive 2 miles to the tip, let along 200, at the end of it.
I do as I said however advocate the idea of applying tachographs and "EU rules" to taxi and private hire drivers, though, having seen some incredibly irresponsible acts by taxi drivers, such as the usual practice[1] in MK of doing the night shift then a 5am Luton airport run as the last job, during which drivers are often veering all over the road due to falling asleep. I gave up using taxis for that journey and drove myself in the end, as at least I could control that I had gone to bed a bit early to ensure I was safe, but was not a fan of sharing the road with those who self-evidently weren't.
[1] Allegedly it's against the rules of at least one of the companies, but they do nothing to enforce it. An advantage of a pure app-based system without manual intervention like Uber is that they could enforce it by refusing to provide too much work - but they aren't going to do that unless the law levels the playing field by requiring it.