Depends on the context.
Even Usain Bolt can't quite get there.
It would be a pitiful tennis serve.
You'd have zero chance of remaining upright getting onto an escalator going that fast.
And for vehicular traffic in built up areas the limit could usefully be below it.
Any car built in the past 20 years can stop from 30 within 6 foot.
Wow - that's impressive. An average acceleration of 5g.
I hope you'll understand if I say I don't believe you.
My 2.3 ton A6 could stop in less than that.
Nor do I believe that.
And please, don't start with the reaction time rubbish.
If one has 5 second reaction time simply should not be driving.
Nobody has mentioned it at all, least of all a rubbish 5s time, until you just did.
But then spouting rubbish seems to be the one thing you are good at.
I take that you don't drive.
You really are determined to prove that you and reasoned thought have never even heard of each other, aren't you.
No, nothing wrong with me.
You say that, and yet as we shall see, it isn't true.*
Name one sane country where they have 20 km/h limit in their highway code.
I can't comment on whether they have a "highway code", but they do have traffic regulations in Belgium (and Mexico, Macao, The Philippines, Ukraine, Switzerland, Georgia and Russia), and all have 20kph speed limits.
[Is this where you show that your edifice of false beliefs includes your attitude to foreign countries?]
Some retarded politicians in Europe have set a 20km/h limit on a handful of roads, mainly to get their names on the papers.
That's about it.
Wrong.
In Belgium, for example, a 20kph limit applies to
all residential streets.
So whoever told you that about retarded politicians and a handful of roads was either stupidly ignorant, or was lying to you. Maybe
they were "retarded politicians".
In any event you shouldn't listen to them - they are doing you no favours at all in encouraging you to go through life believing things rooted in falsehoods.
We already have lowest speed limits in the world
No, we really don't.
https://en.wikipedia.org/wiki/Speed_limits_by_country
So that's something else you believe which is untrue.
* and the war on motorists continues by lowering them further.
And there it is.
There is no "war on motorists". Seriously - what
is wrong with you?
Speed does not kill, it's reckless drivers who kill, the ones using phones whilst driving for example, or the cyclists trying to squeeze in gaps that don't exist next to lorries.
So to what
do you attribute the reductions in accidents and casualties seen in areas where speeds have been reduced?