[Lord Dave]

https://paultan.org/2022/07/12/intelligent-speed-assistance-isa-to-be-mandatory-in-europe-for-new-vehicles-introduced-from-this-month/


Summary: New cars, in the EU, must now have systems which first warn then forcefully slow a car to the posted speed limit.

[AATW]

The speed limits in the UK are bullshit, particularly on motorways.
It's 70mph. It comes from an era where cars were nowhere near as safe and braking systems were nowhere near as good as they are now.
Pretty much everyone goes faster than 70 and there's no serious enforcement. IMO they should make it higher (I reckon 90) and then enforce it properly.

[Iceman]

That’s funny because the highest posted speed limits I’m aware of in North America are 80mph. 80 seems plenty fast even on a continent this size and an interstate highway that smooth. Still took like 6 hours to cross Montana though :/

Guess it just comes back to the old saying that Europeans think 100km is a long way and North Americans think 100 years is a long time.

[WTF_Seriously]

The speed limits in the UK are bullshit, particularly on motorways.
It's 70mph. It comes from an era where cars were nowhere near as safe and braking systems were nowhere near as good as they are now.
Pretty much everyone goes faster than 70 and there's no serious enforcement. IMO they should make it higher (I reckon 90) and then enforce it properly.

Perhaps an 'auto limiter' will spur that to happen.  Everyone exceeds the limit in the states as well.  Generally you're not at risk of violation until you start exceeding 5 mph over the posted limit.  No matter the posted limit, the majority will exceed it at least to that point.  Here, if the safe limit is deemed 80 and the posted speed is 80 everyone will simply drive 85+. Hell, if the safe speed is deemed 80, the posted speed needs to be 70 as there will still be a good many folks that will push 80.  With an 'auto limiter' you could actually post the speed as 90 and no one would ever exceed it.

[Lord Dave]

Would never get passed in America.
Americans love their freedom to do what they want too much to care about safety.

Also cops need speeding tickets to survive.

[xasop]

Pretty much everyone goes faster than 70 and there's no serious enforcement. IMO they should make it higher (I reckon 90) and then enforce it properly.

145 km/h would make it the highest posted speed limit anywhere in Europe. (It is legal to drive faster on some German autobahns, but only because they lack any limit whatsoever.) An abrupt switch from one of the lowest motorway speed limits in Europe to the highest on the entire continent does not sound like a very wise idea.

121 or 129 km/h would be more in line with international norms, and be a smaller change to measure the effect of as a first step. You could even try using the nicer round numbers of 120 or 130 km/h, but that might be too tough a pill for the British to swallow.

[Fortuna]

Anything faster than 70/75 is pretty reckless. No one needs to be going that  fast. If you want to drive fast, go to a racetrack. I hope we get something like this in the US.

[AATW]

Pretty much everyone goes faster than 70 and there's no serious enforcement. IMO they should make it higher (I reckon 90) and then enforce it properly.

145 km/h would make it the highest posted speed limit anywhere in Europe. (It is legal to drive faster on some German autobahns, but only because they lack any limit whatsoever.) An abrupt switch from one of the lowest motorway speed limits in Europe to the highest on the entire continent does not sound like a very wise idea.

121 or 129 km/h would be more in line with international norms, and be a smaller change to measure the effect of as a first step. You could even try using the nicer round numbers of 120 or 130 km/h, but that might be too tough a pill for the British to swallow.

My point is it actually wouldn’t be an abrupt change. All it would do is reflect the reality of what already happens. On a UK motorway most people do 80, certainly in the fast lane. 90 is not that uncommon. You get the occasional idiot who wants to zoom along at over 100 but that’s rare.
I have hit 100 and that does feel pretty fast, I don’t think that is safe for most drivers. 90 feels ok though.

The current state is the limit is 70 but no one sticks to it. You go 70 in the fast lane and you’re going to get people zooming up behind you flashing their lights. So if they want to have a 70 speed limit because they think that’s the fastest anyone can drive safely then ok, but enforce it then. Or, given that no one sticks to that limit, adjust the limit to what currently happens and then enforce it properly to stop all the idiots who want to zoom along at 100 and more. I’d suggest that cars have got a lot safer since the 70 limit was set so why not adjust the limit to reflect that.

EDIT: I’m talking about in good driving conditions. Obviously the limit should be adjusted depending on the conditions, but they already do that.

[Fortuna]

Americans are too dumb to drive 90. British people probably are too. The case for 90 might be made if you're a good driver and have a sports car that can brake and handle very well. But most people over here are driving boat sized SUVs and pickups while talking on their phones.

[AATW]

Americans are too dumb to drive 90. British people probably are too. The case for 90 might be made if you're a good driver and have a sports car that can brake and handle very well. But most people over here are driving boat sized SUVs and pickups while talking on their phones.

They've cracked down pretty hard on people using their mobiles while driving over here although that is hard to enforce.
80 would be a reasonable compromise, that always feels pretty safe to me. 90 I'd vaguely agree feels a bit fast but it's not uncommon over here. My general point is they should set a limit and enforce it. Right now the situation is the limit is 70. Everyone goes 80 minimum in the fast lane and 90 is pretty common. There's no consequence, they say there are speed cameras everywhere but if they were being strict then you wouldn't have everyone going at 80+. So just pick a limit and enforce it. And I personally think that limit should be more than 70 given everyone goes that fast anyway and I don't think serious crashes on motorways are so common that it's a problem.

[DuncanDoenitz]

Speed is just what you get used to.  Back in the 70's in the UK, there was an absolute limit of 50 mph due to some fuel crisis shenanigans; 50 on main roads, 50 on dual carriageways, 50 on motorways.  For about a year.  It took like an age to get anywhere, but people got used to it. 

When the limit was eventually scrapped, to the 60/70 mph the UK has now, driving at 65 seemed absolute madness for the first 20 minutes, but you get used to it.  Take the limit to 80, or 90, and the average speed of traffic may increase as people get accustomed.  And seriously; when was the last time you actually saw a motorway collision caused by excessive speed?  Compared with lack of attention on slower roads. 

And getting back to the OP, yes it would be a safe option if the tech can handle it.  My car has auto-wipers and it would be nice if they only ever wiped a wet screen, and every time; but they don't.  Hate to think that the same level of tech is going to suddenly drop my speed by 10/20 mph. 

[Lord Dave]

It won't be sudden.  I get the impression it'll warn you for a minute or two beforehand.

But how would it know the speed limit?  Read speed signs?  Google map? 


Also, the override is to push harder on the gas pedal.  So.... Its not gonna be THAT much harder.

[AATW]

Take the limit to 80, or 90, and the average speed of traffic may increase as people get accustomed.  And seriously; when was the last time you actually saw a motorway collision caused by excessive speed?  Compared with lack of attention on slower roads.

Right. I think there's a speed over which it is pretty dangerous, for me that's anything above 90. This is subjective but it just feels too fast.
90 doesn't really, often on a motorway I'm going with the flow of traffic and hardly notice if we hit 90.
Motorways don't have sudden turns or traffic lights, you don't (or certainly shouldn't) have people crossing the road.
In light traffic and in good driving conditions it feels fine to me. And the statistics bear that out:

Although motorways carry around 19 per cent of traffic, they only accounted for 5 per cent of fatalities in 2020. The number of people killed on motorways in 2020 was 79, lower than the 105 killed in 2019.

https://www.racfoundation.org/motoring-faqs/safety

And that's in the context of the current way people drive where 80 is routine and 90 common.

[Lord Dave]

The issue with speed is always stopping power.
Faster you go, more time you need to stop.
And human reaction isn't insanely fast.  Average is quarter of a second.

At 90mph that means you'll travel 31 1/2 feet between the time you see something to when you move to brake.

Which is two car lengths. 
And thats just reaction.  Not actually stopping.

[xasop]

My point is it actually wouldn’t be an abrupt change. All it would do is reflect the reality of what already happens.

You mean what actually happens when the speed limit is 113 km/h. Just because people aren't adhering to the speed limit doesn't mean it isn't a factor in their decision of how fast to drive. Human psychology is not that simple.

It is a basic scientific principle to make small adjustments and find out what effect they have before trying larger ones, especially where safety is concerned. So, even if the ultimate goal is a speed limit of 145 km/h, such a large step should not be the first.

[AATW]

The issue with speed is always stopping power.
Faster you go, more time you need to stop.
And human reaction isn't insanely fast.  Average is quarter of a second.

At 90mph that means you'll travel 31 1/2 feet between the time you see something to when you move to brake.

Which is two car lengths. 
And thats just reaction.  Not actually stopping.

Yes. But. No-one should be going at 90 - or even 70 - right up the arse of the car in front. You'd only be going that speed in fairly light traffic where there's a decent gap between cars. You can't stop dead because physics. But that same physics means the car in front of you can't either. So even if they do brake sharply for some reason, you should be far enough back that you have time to as well. And as I said above braking technology is a lot smarter than it used to be.

[AATW]

My point is it actually wouldn’t be an abrupt change. All it would do is reflect the reality of what already happens.

You mean what actually happens when the speed limit is 113 km/h.

You mean, of course, 70mph.
We aren't in the EU, stop confusing me with your complicated metric system.
It's what happens when the speed limit is 70 and people know it's not enforced.
So right now you do get the occasional idiot doing more than 100, because they know they can.
If you make it 90 and actually enforce it then those idiots would have to stop doing that, because otherwise they'd get banned.
And the rest of us could keep driving as we do.

But 80 as a stepping stone would be fairly reasonable, I guess. I'm not particularly convinced it's needed though.

[Iceman]

Yes. But. No-one should be going at 90 - or even 70 - right up the arse of the car in front.

Have you met city drivers?

You can’t make laws based on the skills of the more competent and reasonable parts of the population unfortunately. If you raise the speeds of the average of the flow of traffic, you raise the speed of the average impact.

I spend a lot of time on the road and while I’d agree that many posted limits are on the conservative side. Spiking them up too far would have some very notable consequences.

People just aren’t smart enough (or at least they overestimate their own skills - something like 80% of drivers think they’re better than average) to reliably adjust their habits based on traffic volume, weather, road conditions, and construction/workers on roadsides.

[AATW]

Yes. But. No-one should be going at 90 - or even 70 - right up the arse of the car in front.

Have you met city drivers?

You can’t make laws based on the skills of the more competent and reasonable parts of the population unfortunately. If you raise the speeds of the average of the flow of traffic, you raise the speed of the average impact.

I spend a lot of time on the road and while I’d agree that many posted limits are on the conservative side. Spiking them up too far would have some very notable consequences.

People just aren’t smart enough (or at least they overestimate their own skills - something like 80% of drivers think they’re better than average) to reliably adjust their habits based on traffic volume, weather, road conditions, and construction/workers on roadsides.

It's impossible to know for sure what impact my suggestion would have. My hope is it would stop the real idiots - the people who whizz around at 100mph+ - while leaving the rest of us to drive how we already do. Some people are content on motorways to pootle down the slow lane at 60-70. If they want to do that then fine, but most people prefer to go at 80-90. This is technically illegal but it's not enforced. While I agree people are, by and large, idiots, I actually don't think you have to be a particularly good driver to drive that fast on a relatively quiet motorway. It's a mostly smooth road surface with no obstructions or sharp bends. If the traffic is light enough for it to flow at 80-90 then it doesn't feel particularly dangerous. And the statistics show that UK motorways are not a bloodbath. Driving fast on a motorway feels safer than in city driving where there are all kinds of potential hazards.
I don't think that increasing the limit to 90 would mean the "slow" lane would now be zipping along at 90 and the fast lane going even faster because if it was enforced properly then you shouldn't get anyone going faster than that anyway.

[xasop]

It is worth noting that there are a variety of factors to consider other than road safety. Even if the current speed that people drive isn't unsafe, that doesn't mean it isn't causing too much noise pollution, or emitting too much CO₂, or creating congestion problems in urban areas as traffic has to slow down to city speeds. All of these factors, and probably others that I am unaware of, need to be modelled and taken into account when setting speed limits.