Let's devise a sensible national speed limit

[Somewhatfoolish]

Assuming there should be a speed limit on roads, let's see if we can think of one on first principles that should not be exceeded on any road whatsoever.

I will start with Mach 1. Firstly, this creates a sonic boom, so is fking loud. Secondly, it prevents anyone from being able to hear oncoming traffic. Therefore this speed should be illegal in all circumstances on the public highway.

I suspect the next obvious higher bound will be related to the ability of the human eye to pick up an obstacle on the highway that could materially interfere with the car. Be nice if other folk with more knowledge could work that one out for me, otherwise I shall do it later.

Any more ideas to create an upper bound?

[Somewhatfoolish]

Another idea that came into my head: It has to be possible for observers to be able to gauge your speed before pulling out in front of you, without risk of collision. Again, I can work this out on Sunday if I really have to, but would prefer it if someone else could. This will quite possibly lead to different speed limits in different lane-d carriageways.

I want to be clear that this is not a sensible attempt to set a national speed limit; I don't believe that there should be any such thing. But if there is to be such a thing, it ought to be a speed which it is always unsafe to exceed. Sixty or seventy are pathetic jokes... there is no way that anything less than three hundred is justifiable.

Edited by Somewhatfoolish on Friday 25th February 20:36

[Somewhatfoolish]

hehe, just thought of another one

has to be less than mach 0.5. Otherwise the top end of your wheel is travelling supersonic. Or have I not thought this through properly?

edit: no I haven't thought that through properly. It's rubbish. But leaving it as an example of the kind of things we need to think of!

[Somewhatfoolish]

Chaps I agree with you both but that isn't what I'm after. I want to decide a speed limit it is unsafe to exceed on any road at all with any vehicle!

[Somewhatfoolish]

streaky said:

The Germans do OK with speed differentials of over 100mph. But the issue is not so much with a slower driver gauging the speed of an approaching vehicle that one can see, as with seeing an approaching vehicle that is travelling at very high speed in sufficent time to take appropriate action (and v.v.).

Streaky

This variability is not an issue as there's no reason a car couldn't have a machmeter installed.

However I don't think mach 1 is likely to be safe on any road in the UK. I think 300mph could be in some places, certain rural motorway stretches mainly. But what is the best way to find an absolute limit, that's the main focus of this thread...