Speed limiters in cars

[Meerkat]

Do the many vehicles that already have speed limiters cause problems with safety that outweigh the benefit? For example HGVs limited at 56 mph and coaches limited at 62 mph. Some London buses have speed limiters that can adjust automatically to 20 mph and 30 mph zones. Are these dangerous?

Well you get some pretty dangerous bunching when lorries hit their limiters when overtaking on dual carriageways.
Its safer to overtake quickly. Anyone saying that you shouldn’t overtake clearly hasn’t been stuck behind all the people with more over-reading speedos (or had a lorry right up their jacksie in an average speed 50 because they have a more accurate speedo!).

 

[AM9]

Well you get some pretty dangerous bunching when lorries hit their limiters when overtaking on dual carriageways.
Its safer to overtake quickly. Anyone saying that you shouldn’t overtake clearly hasn’t been stuck behind all the people with more over-reading speedos (or had a lorry right up their jacksie in an average speed 50 because they have a more accurate speedo!).

Being stuck behind vehicles doing two mph less than the speed limit isn't justification for high risk overtaking manoeuvres. It's just five seconds per mile slower. Remember that speed limits are maximum speeds, -1 not a target irrespective of road conditions.

 

[johncrossley]

Well you get some pretty dangerous bunching when lorries hit their limiters when overtaking on dual carriageways.
Its safer to overtake quickly. Anyone saying that you shouldn’t overtake clearly hasn’t been stuck behind all the people with more over-reading speedos (or had a lorry right up their jacksie in an average speed 50 because they have a more accurate speedo!).

Would you prefer HGVs to have their limiters removed or have their limiter increased? I found it quite scary driving in the US where trucks can typically go 65 mph and in some states there is no lower limit for trucks. They also seem to be quite capable of exceeding the limit and travel at similar speed to cars.

 

[Meerkat]

Being stuck behind vehicles doing two mph less than the speed limit isn't justification for high risk overtaking manoeuvres. It's just five seconds per mile slower. Remember that speed limits are maximum speeds, -1 not a target irrespective of road conditions.

High risk? The speed limit was set at 70 in the days of all round drum brakes, rubbish tyres and no seatbelt law. Are French autoroutes high risk?

Would you prefer HGVs to have their limiters removed or have their limiter increased? I found it quite scary driving in the US where trucks can typically go 65 mph and in some states there is no lower limit for trucks. They also seem to be quite capable of exceeding the limit and travel at similar speed to cars.

I wasn’t suggesting that, I was just pointing out that speed limiters do cause problems.

 

[LSWR Cavalier]

Trucks could quite easily be fitted with distance sensors to force them to keep apart. Lower maximum truck speeds would be good too, I did not mind drifting along a safe distance behind a truck doing 40 mph on the. A49. Few chances to get by there, even if one may/can do 20 mph more.

 

[Bletchleyite]

Would you prefer HGVs to have their limiters removed or have their limiter increased? I found it quite scary driving in the US where trucks can typically go 65 mph and in some states there is no lower limit for trucks. They also seem to be quite capable of exceeding the limit and travel at similar speed to cars.

With regard to overtaking, I'd just suggest a bit more common sense from their drivers and not bothering with these overtakes when the speed differential is just 1mph or so. Or perhaps more accurate limiters so the differentials don't arise in the first place.

That said, I probably wouldn't object to the idea of both coach and lorry limiters being changed to a round 60mph when driven in the UK rather than 56 and 62 based on km/h speed limits that don't apply to the UK.

 

[johncrossley]

Trucks could quite easily be fitted with distance sensors to force them to keep apart. Lower maximum truck speeds would be good too, I did not mind drifting along a safe distance behind a truck doing 40 mph on the. A49. Few chances to get by there, even if one may/can do 20 mph more.

The single carriageway speed limit for trucks was actually increased a few years ago! From 40 to 50 mph on single carriageways and from 50 to 60 mph on dual carriageways, although speed limiters are set to 56 mph.

 

[Bletchleyite]

The single carriageway speed limit for trucks was actually increased a few years ago! From 40 to 50 mph on single carriageways and from 50 to 60 mph on dual carriageways, although speed limiters are set to 56 mph.

But not in Scotland interestingly!

This was actually a good safety move as it reduced risky overtaking by car drivers. Most car drivers will be "happy" doing 50mph and stay behind the lorry, whereas 40mph feels too slow and so they are more likely to attempt an overtake which carries considerable risk. And on 50mph limited speed-camera fitted single carriageways, of which there are a fair few, overtaking by cars of lorries is mostly no longer a thing.

 

[LSWR Cavalier]

Yes, I remember the change, giving in again. I wonder how many lives it has cost.

 

[Bletchleyite]

Yes, I remember the change, giving in again. I wonder how many lives it has cost.

See my explanation as to why this change has most likely saved rather than cost lives - it was done for safety reasons, not as a sop to the industry. Overtaking is by far the most dangerous activity on single carriageways, not driving a bit faster. The change has considerably reduced overtaking of lorries by cars on single carriageways, because most car drivers will happily sit at 50 or so on a single but most will not happily sit at 40 so will attempt to overtake, often dangerously.

 

[johncrossley]

The single carriageway speed limit for cars in the UK is quite generous compared to most European countries. In most of Europe it is either 80 or 90 km/h. The Flemish region of Belgium even has a 70 km/h limit. Countries with such limits might allow 100 km/h on higher standard single carriageway roads. The UK allows 60 mph on most narrow country lanes, where even 40 mph might be risky, which leads to anomalies when lower speed limits are imposed on main roads. So you might be on a 50 mph single carriageway road with average speed cameras, and then you turn off onto a narrow country lane where the limit increases to 60 mph!

 

[Bletchleyite]

The single carriageway speed limit for cars in the UK is quite generous compared to most European countries. In most of Europe it is either 80 or 90 km/h. The Flemish region of Belgium even has a 70 km/h limit. Countries with such limits might allow 100 km/h on higher standard single carriageway roads. The UK allows 60 mph on most narrow country lanes, where even 40 mph might be risky, which leads to anomalies when lower speed limits are imposed on main roads. So you might be on a 50 mph single carriageway road with average speed cameras, and then you turn off onto a narrow country lane where the limit increases to 60 mph!

The UK has tended to take a more libertarian line than the likes of Italy where almost every road has a posted limit and they typically vary up and down based on what's sensible to do at that point. There is no intention for people to do 60mph on single track country lanes, and indeed people hardly ever do. The sign is derestriction - "use your judgement up to 60mph", not "drive at 60mph regardless".

To be honest I'd support a reduction in NSL to 50 on singles and 60 on duals (keeping 70 on motorways), this would near enough remove dangerous overtaking entirely. You could have the option to sign some pseudomotorway duals up to 70 by displaying 70 rather than derestriction signs plus repeaters.

 

[AM9]

High risk? The speed limit was set at 70 in the days of all round drum brakes, rubbish tyres and no seatbelt law. Are French autoroutes high risk?

I think that you've missed the point of my post. In your post #61 you said: "Well you get some pretty dangerous bunching when lorries hit their limiters when overtaking on dual carriageways.
Its safer to overtake quickly. Anyone saying that you shouldn’t overtake clearly hasn’t been stuck behind all the people with more over-reading speedos (or had a lorry right up their jacksie in an average speed 50 because they have a more accurate speedo!)."
Overtaking vehicles travelling just 2mph slower is the risk. Making such hazardous manoeuvres to save just 5 seconds per mile is taking a risk for little or no gain. If an arrival time is that important then tinsufficient time was allowed for the journey, - a major cause of many road incidents.

 

[ABB125]

But not in Scotland interestingly!

Apart from the A9. Such a simple, easy to understand system...

 

[87 027]

I don't think anyone would disagree that excess speed is dangerous (i) at high levels absolutely and (ii) at lower levels where it is inappropriate for the locality and situation. However this thread was started on the premise that something could be done to remove control from drivers to address situation (ii). I remain unconvinced that present day technology provides a sufficiently reliable solution without introducing potential downsides elsewhere although I acknowledge that this situation might change in the future.

I have done more motorway driving this year than in the last few years combined and am frankly appalled at the behaviour of some HGV drivers. The M1 and M6 both have long stretches of road works where smart motorways are being installed, with average speed cameras; I have set my cruise control to the limit based on GPS (rather than the speedo which overreads by 2-3 mph) and lost count of the number of times I have been aggressively tailgated by lorries in lanes 1 and 2

 

[JohnMcL7]

Speaking of the A9, when they raised the HGV speed limit they also fitted a system of average speed cameras replacing a handful of Gatsos near the Perth end. There were a lot of complaints at the time about them being installed which I thought odd because I think they're a fair way of doing it, there's lots of warning and they're spaced reasonably apart so a few brief overtakes won't put you over the limit.

I've found in practice there's a noticeable improvement as there would often be dangerous overtakes particularly with people trying to leap frog up long queues. There are some slight downsides with people being less willing to overtake HGV's even though it's not going to affect their average speed and you still get people doing mad overtakes near the end of the dual carriageway even though everyone is going to drop to 60mph. There's also still people out there who don't understand average camera systems and slam on the brakes going past each gantry.

I agree with the post above I'm certainly in favour of limiting speeds where possible but only where the technology is workable which I don't think it is yet. The talk of race tracks may suggest I don't want limiters set because I speed but it's not the case, I've never had any points which is because I'm a slow and boring driver. I like going to the race track to push a car where it's far safer to me and everyone else plus it gives you an appreciation of the danger speed can be. It's surprising how quickly you come into corners, how much longer it takes to break and how easily you can slide the car.

 

[90019]

Apart from the A9. Such a simple, easy to understand system...

Ah yes, the 'trial' 50mph speed limit on the A9.

A trial which has now been going for six and a half years...

 

[Bald Rick]

At a slight tangent, if we are to have limiters, then we should also have a system that prevents people from driving well under the speed limit on strategic roads when conditions are good. I’m absolutely sick of people tootling along at 40mph on NSL single carriageway roads.

(I’m half serious about this!)

 

[ABB125]

At a slight tangent, if we are to have limiters, then we should also have a system that prevents people from driving well under the speed limit on strategic roads when conditions are good. I’m absolutely sick of people tootling along at 40mph on NSL single carriageway roads.

(I’m half serious about this!)

But it saves fuel so is better for the environment...

(I fully agree though!)

 

[Domh245]

At a slight tangent, if we are to have limiters, then we should also have a system that prevents people from driving well under the speed limit on strategic roads when conditions are good. I’m absolutely sick of people tootling along at 40mph on NSL single carriageway roads.

(I’m half serious about this!)

The sooner humans are no longer in control of vehicles, the better!

 

[krus_aragon]

The GPS position needs to be ultra-accurate and there are examples in the other thread of this not being so at the current time. Specifically a newspaper reporting the example of a car on a motorway slamming on the brakes where a road with a lower speed limit crossed over the motorway

It also depends on the accuracy of the mapping info. A young acquaintance of mine who opted to have a black box fitted by his insurer, found that they black-marked him for speeding on a road where they got the 30/40mph boundary wrong by about 100m. There's also a portion of a 50mph dual carriageway where they assigned one tiny part the speed limit of the 30mph underpass instead, giving him one "black mark" in a sea of green on that journey. The ludicrousness of a few metres of 30mph in the middle of a dual carriageway hadn't been picked up by the company.

In my local area the road which must have the highest amount of speeding is a few miles of 50mph dual carriageway, sandwiched by 30 miles plus of a continuous 70mph limit. (The road itself doesn't change in quality, but has a lower speed limit as that section is through a town and has substandard short sliproads)

That's the road: it's the Marine Road underpass.

 

[Bald Rick]

The sooner humans are no longer in control of vehicles, the better!

Personally my vote is for a much higher standard of driving test, with compulsory retakes every 5 years. That would sort out the wheat from the chaff.

 

[Domh245]

Personally my vote is for a much higher standard of driving test, with compulsory retakes every 5 years. That would sort out the wheat from the chaff.

I certainly wouldn't object to that as part of the move to driverless! It's in some ways terrifying that the UK is one of the better countries when it comes to driving standards

 

[Bald Rick]

I certainly wouldn't object to that as part of the move to driverless! It's in some ways terrifying that the UK is one of the better countries when it comes to driving standards

Arguably the best. The only place I’ve driven with driving as good as ours is Switzerland. I suspect Scandinavia is good too, but then they have much emptier roads, generally. And more Volvos

 

[zwk500]

Personally my vote is for a much higher standard of driving test, with compulsory retakes every 5 years. That would sort out the wheat from the chaff.

Agree with this (well 10 years rather than 5, but that's detail). Also an intermediate stage between Learner and Qualified, with a separate test to qualify proper, to allow experience to be built up in more controlled way.

 

[61653 HTAFC]

The sooner humans are no longer in control of vehicles, the better!

Yes, let's make roads utterly impossible for pedestrians to cross at grade, that won't be a disaster at all. Even better, let's give control of our entire road traffic system over to a sociopathic manchild... Yay!

Self-driving cars in the way that advocates imagine them (and that Mr. Grimes' bad CGI renders depict them) are still a very long time off becoming viable, if they ever do. What exists at the moment is better described as "driver assist" but TeslaBro calls it Autopilot so the media just wet themselves and say "ooh, magic cars!!!1"

Yes, humans are unreliable and make mistakes all the time... and that sucks. The difference is that if a human makes a mistake (or worse, behaves irresponsibly or recklessly) on the road, society can sanction that human. Try doing that when something goes awry with a self-driving car.

 

[Domh245]

Yes, let's make roads utterly impossible for pedestrians to cross at grade, that won't be a disaster at all. Even better, let's give control of our entire road traffic system over to a sociopathic manchild... Yay!

Self-driving cars in the way that advocates imagine them (and that Mr. Grimes' bad CGI renders depict them) are still a very long time off becoming viable, if they ever do. What exists at the moment is better described as "driver assist" but TeslaBro calls it Autopilot so the media just wet themselves and say "ooh, magic cars!!!1"

Yes, humans are unreliable and make mistakes all the time... and that sucks. The difference is that if a human makes a mistake (or worse, behaves irresponsibly or recklessly) on the road, society can sanction that human. Try doing that when something goes awry with a self-driving car.

I dislike Elon and his fanboys just as much as you do, don't worry. I very much hope whatever the future holds, he plays no role!

At-grade crossings can be solved with enough willpower (you could have some sort of stop signal that the car can read, which is activated by a pedestrian pushing a button to indicate they want to cross the road, for example. Maybe you could have different sorts of interfaces and name them after birds!)

Solve the ethics/responsibility issues (or perhaps even better, separate the 2 ton death boxes and the squishy pedestrians/cyclists) and all the other technological hurdles and there's no reason not to have driverless cars. I'm under no illusion that it's several decades away yet

 

[61653 HTAFC]

I dislike Elon and his fanboys just as much as you do, don't worry. I very much hope whatever the future holds, he plays no role!

At-grade crossings can be solved with enough willpower (you could have some sort of stop signal that the car can read, which is activated by a pedestrian pushing a button to indicate they want to cross the road, for example. Maybe you could have different sorts of interfaces and name them after birds!)

Solve the ethics/responsibility issues (or perhaps even better, separate the 2 ton death boxes and the squishy pedestrians/cyclists) and all the other technological hurdles and there's no reason not to have driverless cars. I'm under no illusion that it's several decades away yet

We tried separating pedestrians from traffic in the 1960s and 1970s, and in most places it destroyed any sense of community that existed because we insisted that the 2-ton death boxes could move freely and unimpeded at 40+ mph. The peasants, sorry pedestrians, were banished to concrete skywalks or worse, subways.
Better to slow them down, whether they're being driven by a magic infallible computer or 18year old Daz off the estate.

 

[philthetube]

Realistically it wouldn't work. Having a fixed upper speed limit won't eliminate the problem of a motorist blasting along at 60 passed a school at chuckout time. SatNavs regularly demonstrate GPS isn't reliably accurate enough to enforce speed limits and may well kick in at a moment that actually puts a road user in danger such as during an overtaking maneuver, or to avoid a collision. Besides, pool cars would simply have the limiter bypassed. They aren't taxed or insured and won't be road legal for a number of reasons so a speed limiter being defeated isn't going to make any difference...

You can look at any invention and say that, nothing is perfect and cures everything, it would prevent some issues, would you say that 30mph speed limits don't work for the same reasons?

 

[zwk500]

You can look at any invention and say that, nothing is perfect and cures everything, it would prevent some issues, would you say that 30mph speed limits don't work for the same reasons?

Its the balance between the problems it causes and the problems it solves. 30mph limits solve more problems, and more important problems, than the ones they cause.
Mandatory limiters, depending on how they were implemented, could cause many more problems than they solve.