Lorries should be disallowed from overtaking. Every day, I see traffic queues as long as you can see behind lorries side by side doing an identical 50 mph (or less if uphill). Today on one occasion, no sooner had the overtaking lorry pulled in, than the overtaken lorry pulled out to overtake again. Yes, I agree, they seem to be very polite about pulling out at the last minute and pulling in as soon as they can, but it does seem that the right indicator, to a lorry driver, means not "I am intending to move right when there is a safe opportunity to do so", but " my indicator is on, therefore I have a right to change lane. If you're in my space in the right lane, bad luck!"
Also, if lorries were banned from overtaking, there would be no advantage in them driving with inches between them, so that problem would be solved also.
No, I don't think lorries have some kind of magical stopping mechanism that makes driving inches apart at 50 safe for them. Braking perfomance is mostly determined by: 1. Delay in seeing the hazzard to appying the brakes. 2. Delay in the braking mechanism (possibly longer for air brakes?) 3. Coefficient of friction between the tyres and the road surface, which can be greatly influenced by temperature water oil etc. but is not influenced by weight (put a 2cv on a set of lorry tyres and it's stopping distance will be largely similar to the fully laden lorry) 4. ABS
