Reducing the default urban road speed limit to 20 mph

[daodao]

Should the rest of the UK follow Wales/Cymru and reduce the default urban road speed limit to 20 mph, as the Senedd decided yesterday?

Speed limit to be lowered to 20mph in Wales

Wales will become the first UK nation to adopt a 20mph default limit speed in built-up areas.

www.bbc.co.uk

Speed limits in built-up areas will be reduced from 30mph to 20mph in Wales from next year - a UK first that is controversial among some drivers.

Ministers have said a 20mph speed limit will lower road collisions and noise and encourage people to walk or cycle.

The slower limit has been divisive in areas where there have been trials with some motorists complaining of more congestion and journeys taking longer.

The Welsh Parliament passed the law in a vote on Tuesday afternoon.

 

[Dai Corner]

Should the rest of the UK follow Wales/Cymru and reduce the default urban road speed limit to 20 mph, as the Senedd decided yesterday?

I do wonder how well this has been thought through. For example, buses will be slower and even less attractive but their costs will increase. More people will drive or get taxis (often ignoring the speed limit as there aren't the resources to enforce it) and pollution and congestion will increase.

To answer the question: No I don't think they should.

 

[Snow1964]

It has been tried in London, but the bus limiters (which TfL call Intelligent speed awareness (ISA) seem to be set at 18mph. The result is frustration and lots of dangerous overtaking.

Bath tried it, but soon discovered the volume of accidents rocketed as people don’t pay much attention at the slower speed, so got rid of it except in local zones near schools and areas with lots of pedestrians.

I grew up near New Forest, and about 35 years ago they introduced a blanket 40mph limit, and number of accidents and animal deaths was higher the year after than before. Simply because the speed limit on open straight stretches of heathland was set identical to narrow bendy parts, so instead of driving to the road conditions they created frustration and bad overtaking where people were used to going quicker.

I am thus against blanket restrictions, regardless of width and risk level of road, much prefer speeds to be set appropriately for conditions that provides a balance between safety and efficient journeys.

So clearly 20mph a bad idea when introduced wholesale, but makes sense is a few high risk zones.

As for Wales I have seen signs for 50mph to cut pollution (which even applies to those in electric cars, but I don’t know how that works if the electricity is generated by solar etc.)

 

[yorkie]

It has been tried in London, but the bus limiters (which TfL call Intelligent speed awareness (ISA) seem to be set at 18mph. The result is frustration and lots of dangerous overtaking.

Bath tried it, but soon discovered the volume of accidents rocketed as people don’t pay much attention at the slower speed, so got rid of it except in local zones near schools and areas with lots of pedestrians.

I grew up near New Forest, and about 35 years ago they introduced a blanket 40mph limit, and number of accidents and animal deaths was higher the year after than before. Simply because the speed limit on open straight stretches of heathland was set identical to narrow bendy parts, so instead of driving to the road conditions they created frustration and bad overtaking where people were used to going quicker.

I am thus against blanket restrictions, regardless of width and risk level of road, much prefer speeds to be set appropriately for conditions that provides a balance between safety and efficient journeys.

So clearly 20mph a bad idea when introduced wholesale, but makes sense is a few high risk zones.

As for Wales I have seen signs for 50mph to cut pollution (which even applies to those in electric cars, but I don’t know how that works if the electricity is generated by solar etc.)

Any sources for these claims (hyperlinks and quotes please)?

People who engage in dangerous behaviour should lose their licenses permanently and more should be done to detect such behaviour.

 

[johncrossley]

Intelligent speed awareness (ISA)

is going to be implemented in all new cars in the near future.

 

[Bletchleyite]

As a utility cyclist I dislike 20s. I don't typically cycle at 20mph (unlike the Lycra-wearing campaigners), and so 20mph means the threat (overtaking car) is alongside me for a third longer than otherwise.

As a driver I don't overly mind them in the right setting, I put it in third gear and set the limiter. However I prefer "20 zones" i.e. where the road is designed such that 20 is a comfortable speed to drive by placing chicanes, "natural chicanes" (parking, planters etc) and table junctions etc in strategic locations.

I suspect that's not the way round they wanted and thus I don't support this proposal.

As for Wales I have seen signs for 50mph to cut pollution (which even applies to those in electric cars, but I don’t know how that works if the electricity is generated by solar etc.)

As a slight aside I support changing NSL to 50-60-70 single-dual-motorway for all vehicles (other than where mandatory limiters reduce it, so for lorries in practice it'd be 50-56-56 and coaches it'd be 50-60-62). It near enough eliminates single-carriageway overtaking (other than of cycles and tractors) which is a significant safety benefit, and having driven on plenty of 50-signed singles in places like the Peak District you lose hardly any time driving at 50 and get a far more relaxing experience, plus less pollution from braking and accelerating frequently. (You can of course choose to drive at 50 in a 60, but that frustrates people and causes dangerous overtakes, so the lower limit is better). 60 on non-motorway duals also reduces risk (driving at 70 on many of them is like a roller coaster, e.g. the A1 where they've kept the old single as one carriageway and added another), and I'd apply 60 to any non-hard-shouldered motorways too.

 

[LSWR Cavalier]

Very good, but in practice it will mean vehicles doing 20+x instead of 30+y.

Looking forward to reading complaints about having trouble going slower, and increased fuel use at low speeds. Perhaps switching off the engine while not moving could be encouraged too.

 

[thejuggler]

I live in the middle of a largely 20 limit area and I visit Cardiff to a largely 20 limit area. I have no issue with it.

Speaking to a traffic engineering friend the reasoning behind 20 limits is to reduce the average road speed to well below 30 mph. In 30 limit areas very few drivers choose to do less than 30 where that speed is possible.

 

[Bletchleyite]

Very good, but in practice it will mean vehicles doing 20+x instead of 30+y.

Without cameras, people typically do about 5 over in lower limits. 25 is still 5mph slower than 35, and of course you've got speedo error so they're probably actually about 22 and 32.

Looking forward to reading complaints about having trouble going slower, and increased fuel use at low speeds.

To be fair the most efficient speed for an ICE car is about 55mph, this is why the US used that limit for so long and still do in many places.

EVs are most efficient at 1mph, though, and obviously we are planning for the future here.

Perhaps switching off the engine while not moving could be encouraged too.

Pretty much every modern car does that automatically unless the auxiliary load is too high or the battery is in poor condition.

 

[Dai Corner]

It's worth noting, perhaps, that the Welsh Deputy Minister for Climate Change (whose responsibilities include transport and roads) is a former Director of Sustrans Cymru, the cycling lobbyists.

Pretty much every modern car does that automatically unless the auxiliary load is too high or the battery is in poor condition.

Or the driver has turned the functionality off or holds the car on the foot brake instead of putting it in neutral and engaging the handbrake.

 

[yorkie]

Better than having a pro-car lobbyist!

I came across 2 angry car drivers who drove at inappropriate speeds yesterday and did unsafe overtakes, one of them also approached a group of children at speed and drove far too quickly over a zebra crossing outside a school.

We should not pander to them and say "but if we lower the speed limit, those people will get frustrated"; no, we should be doing more to identify those people and ban them.

 

[Bletchleyite]

Or the driver has turned the functionality off or holds the car on the foot brake instead of putting it in neutral and engaging the handbrake.

True, but you can't really legislate* for stupidity. Though personally I would like to see holding on the clutch/footbrake at traffic lights prosecuted as one of the "due care" offences, as it tends to result in a rear-ending causing damage/injury in more than one vehicle because if hit from behind you naturally release the brake and roll forward yourself, or may even slip off the clutch and power forward into the car in front. The handbrake (or Park in an auto if you prefer) should be used until the light changes. Alongside sitting too close to the vehicle in front in a queue, which poses the same danger; a good guideline is that you should be able to see the vehicle in front's rear wheels or you're too close.

* Well, you can, but it's difficult to enforce and so pointless.

 

[bramling]

Should the rest of the UK follow Wales/Cymru and reduce the default urban road speed limit to 20 mph, as the Senedd decided yesterday?

Speed limit to be lowered to 20mph in Wales

Wales will become the first UK nation to adopt a 20mph default limit speed in built-up areas.

www.bbc.co.uk

No.

From having spent a fair amount of time in Wales recently, I get the feeling many of the traffic calming measures are politically induced, rather than being intended to be effective. Parts of South Wales in particular have massive amounts of measures like speed bumps, often in places which simply result in having to come to a near stand right at the bottom of a hill (so hardly great for pollution) as well as imposing significant wear on vehicles which isn’t a good thing either.

I’m not quite sure what Wales expects. Most of the ex-industrial south has no rail service. You have town after town that’s heavily populated, and quite simply people need / want to get places. Seems Drakeford doesn’t want people travelling more than 5 miles from home?!

As for effectiveness, as ever the focus should be more on poor / dangerous driving rather than imposing arbitrary speed limits. The former is of course firmly in the too difficult box, simply because if you take dangerous drivers off the road then people bleat about their lifeline being taken away, to which political parties know there will be a fall-out.

 

[Bletchleyite]

It is also worthy of note that this makes buses less attractive by slowing them down further.

I think London has overdone it. I could be tempted to say that residential non-thoroughfare type streets should even be lower - even potentially make them "play streets" with pedestrians/cycles having absolute priority (i.e. the whole road is legally a zebra crossing) and all overtaking including of cycles prohibited (this may even be more effective than low-traffic neighbourhoods in preventing rat running). But for main thoroughfares 20mph is pointlessly slow, and as noted above as a cyclist I dislike them.

 

[Bald Rick]

It’s worth pointing out that in some (If not all) places, police forces treat 20 limits as “self enforcing”. That’s certainly the case here in Hertfordshir.

 

[Bletchleyite]

It’s worth pointing out that in some (If not all) places, police forces treat limits as “self enforcing”. That’s certainly the case here in Hertfordshir.

That's why 20 Zones are good - as part of doing them you have to design the road layout so most drivers would choose to do 20mph.

 

[jfollows]

I wouldn't get seriously upset if this proposal were to be implemented in the rest of the UK, but on balance I'm against it.
I agree that 20mph zones, for example outside schools, seem reasonable.
20mph limits seem to be mainly to address the failure of enforcement of 30mph limits.
I don't claim to be a perfect driver at all, but I'm very hot on myself to observe 30mph and 20mph limits.
I did go on a speed awareness course a few years ago (for having been seen driving at 57mph in a 50mph limit) and I found that the majority of participants were there for breaking a 30mph limit.
I also note when observing 30mph limits how many people (but not all) catch up with me, so they're clearly going too fast. This is as much little old ladies as it is boy racers. So there's clearly a problem.
I used to go through a short 20mph section on my way to work and never saw anyone else observe the limit, unless they were directly behind me when they didn't really have a choice.
But a blanket replacement of 30mph with 20mph, it'd probably bring down the speed of people currently driving at 40mph so it's not all bad, but personally it'd be annoying to me and I'm not really in favour.

 

[roversfan2001]

20mph limits (as opposed to 20mph zones for the reasons stated upthread) are entirely pointless and are fairly universally ignored by drivers.

 

[jfollows]

20mph limits (as opposed to 20mph zones for the reasons stated upthread) are entirely pointless and are fairly universally ignored by drivers.

That's certainly my experience, too.
I went on a driving course a few years ago offered by my work, which was useful. One of the participants said that she found it hard to drive "slowly" ie at 30mph and certainly at 20mph, so I think the instructor tried to help her out of this mindset and learn how to driver properly at slow speeds. So I suspect others have the same "problem", which is really just poor driving, but which can be cured.

 

[Bletchleyite]

That's certainly my experience, too.
I went on a driving course a few years ago offered by my work, which was useful. One of the participants said that she found it hard to drive "slowly" ie at 30mph and certainly at 20mph, so I think the instructor tried to help her out of this mindset and learn how to driver properly at slow speeds. So I suspect others have the same "problem", which is really just poor driving, but which can be cured.

In most vehicles it is fairly hard to drive smoothly at low speeds. You do have to concentrate very hard. Using 2nd gear helps, but in powerful cars that makes it too jumpy, whereas the engine will labour in third or fourth, or you get "turbo lag" jerkiness in many diesels.

It's much easier in vehicles with a settable limiter. I always set it for 20 limits, sometimes even use cruise control if it's not busy.

 

[johncrossley]

I also note when observing 30mph limits how many people (but not all) catch up with me, so they're clearly going too fast. This is as much little old ladies as it is boy racers. So there's clearly a problem.

By being a law-abiding citizen, you are punished by more people tailgating you. Then sometimes they even overtake you. That shows they have blatant disregard for the limit, and they aren't speeding by accident.

 

[roversfan2001]

By being a law-abiding citizen, you are punished by more people tailgating you. Then sometimes they even overtake you. That shows they have blatant disregard for the limit, and they aren't speeding by accident.

Of course, if your speedo says 30/40/50 etc. then in reality you're doing anything up to 10% less than that.

 

[Bletchleyite]

By being a law-abiding citizen, you are punished by more people tailgating you. Then sometimes they even overtake you. That shows they have blatant disregard for the limit, and they aren't speeding by accident.

One thing I've noticed in Milton Keynes is that 20s, 30s and 40s are almost 100% respected despite there basically being no enforcement whatsoever*. People don't even seem to go a bit over in most cases, they stick to it religiously. To me, the key reason for this is that limits are generally high so there isn't a feeling that they're an impingement on the motorist, rather there's an understanding that where there are lower limits, they're there for a reason.

A 20 default (alongside 30s rather than 40s on segregated urban duals) is the complete antithesis of this and breeds disrespect.

* I know of I think 2 fixed cameras in the whole city, and very rarely do the Police get the gun out (seen it once ever), and there's no local partnership van I know of.

 

[RailWonderer]

No, we should be increasing speed limits in some areas if anything because cars are safer nowadays. We need to reduce journey times, add lanes and reduce congestion and not continue a war on the motorist. The breaking distances in the highway code are based on a 1965 Ford Anglia, which is beyond ridiculous. We need to level up our roads more like Germany, instead of lagging behind. 20mph zones in areas of schools and high pedestrian traffic are fine, but not a blanket 20mph reduction. In my area we have a smart limit where the speed limit is 20 in school hours and 40 outside.
More smart speed areas are a better solution.

I came across 2 angry car drivers who drove at inappropriate speeds yesterday and did unsafe overtakes, one of them also approached a group of children at speed and drove far too quickly over a zebra crossing outside a school.

We should not pander to them and say "but if we lower the speed limit, those people will get frustrated"; no, we should be doing more to identify those people and ban them.

It's only a minority of people who have casual disregard for everyone around them. People like me just don't appreciate an entire rule change for all just for the sake of a few idiots who will still break the limits even if they are reduced.

 

[Bletchleyite]

Of course, if your speedo says 30/40/50 etc. then in reality you're doing anything up to 10% less than that.

Fairly easy with a manual limiter to work yours out using GPS. I set 21, 31, 41, 52, 62 and 73 on mine to be pretty much "bob on" the limit. They're typically a bit more accurate these days than they were, though on cars where different tyres can be specified they vary more.

What they can't legally do is show even 1mph under, i.e. show 30 when you're going 31.

 

[jfollows]

I also think the argument that because accidents are more serious at 30mph than at 20mph, therefore we should have 20mph limits is fallacious. Firstly because its logical conclusion is that we should drive behind pedestrians walking with a red flag, but less stupidly because I imagine most accidents aren't occurring at the speed limit, but at a lower speed often because the driver was going too fast and wasn't able to stop in time. The point about being able to stop in a distance starting from 30mph, but then comparing this with someone starting at 40mph who would still be going at 30mph if trying to stop in the same distance (the hypothetical child rushing into the road) is a good one.

No, we should be increasing speed limits in some areas if anything because cars are safer nowadays.

In reality, that's never going to happen.
In my area, the extent of the 30mph limits goes further and further out of town, now into pretty open countryside, primarily because of the "something must be done" brigade. I still observe the new limits, but the chance of reversing this trend is nil.

In most vehicles it is fairly hard to drive smoothly at low speeds. You do have to concentrate very hard. Using 2nd gear helps, but in powerful cars that makes it too jumpy, whereas the engine will labour in third or fourth, or you get "turbo lag" jerkiness in many diesels.

It's much easier in vehicles with a settable limiter. I always set it for 20 limits, sometimes even use cruise control if it's not busy.

I don't know, but I suspect you're right. Ironically I found it extremely easy to drive at 20mph and 30mph limits in my last 500bhp car; I think it's harder with "smaller" cars, which are more common, and begs the question why they're designed to make it hard to do so. As you say, a competent driver can work out what to do.

 

[johncrossley]

No, we should be increasing speed limits in some areas if anything because cars are safer nowadays.

Are human reaction times any different?

Are stopping distances any different in other countries?

Looking at this Dutch theory test tutorial:

Auto Theorie Examens Oefenen 2024

Op TheorieExamen.nl kun je theorie examens oefenenen en leren voor het auto theorie examen rijbewijs B van het CBR 2024. Lees het auto theorie boek en vergelijk alle rijscholen in Nederland en deel tips met elkaar op het forum!

www.theorieexamen.nl

At 50 km/h

reaction distance 15 m
braking distance 12.5 m
stopping distance 27.5 m

The UK highway code has a stopping distance of 23 m at 30 mph.

 

[Bletchleyite]

I don't know, but I suspect you're right. Ironically I found it extremely easy to drive at 20mph and 30mph limits in my last 500bhp car; I think it's harder with "smaller" cars, which are more common, and begs the question why they're designed to make it hard to do so. As you say, a competent driver can work out what to do.

I've generally found that in most cars I've had it's easiest to drive in a given limit if you select the gear that is the first number of the limit. That is, 2nd for 20, 3rd for 30, 4th for 40, 5th for 50 and 6th (if you have one) for 60+. The exception is my present Kuga which has hellish turbo lag problems* if you use 6th for anything less than about 65 and gives you a very jerky ride on an undulating road, though it's fine if the road is totally flat. It'd be less noticeable on a traditional large-engined diesel, it's noticeable on this because it's a small engine (1.5) that couldn't pull the skin off a rice pudding until the turbo has spun up.

This is totally counter to what most instructors teach, and to what the flashing warning on the dash says.

* In essence, you're going along happily on the flat, the engine input is so low the turbo isn't spun up, you get to a hill and lose some power, it then takes about a second to get it back as it spins up then you get a nasty jerk, and repeat. Using a lower gear means more exhaust output, which means the turbo stays spinning and it doesn't happen. Even the aircon compressor kicking in is enough to cause it. Took me ages to work out what it was. It's the thing I most dislike about the car, which I'm otherwise very pleased with.

 

[jfollows]

I've generally found that in most cars I've had it's easiest to drive in a given limit if you select the gear that is the first number of the limit. That is, 2nd for 20, 3rd for 30, 4th for 40, 5th for 50 and 6th (if you have one) for 60+. The exception is my present Kuga which has hellish turbo lag problems* if you use 6th for anything less than about 65 and gives you a very jerky ride on an undulating road, though it's fine if the road is totally flat. It'd be less noticeable on a traditional large-engined diesel, it's noticeable on this because it's a small engine (1.5) that couldn't pull the skin off a rice pudding until the turbo has spun up.

This is totally counter to what most instructors teach, and to what the flashing warning on the dash says.

* In essence, you're going along happily on the flat, the engine input is so low the turbo isn't spun up, you get to a hill and lose some power, it then takes about a second to get it back as it spins up then you get a nasty jerk, and repeat. Using a lower gear means more exhaust output, which means the turbo stays spinning and it doesn't happen. Even the aircon compressor kicking in is enough to cause it. Took me ages to work out what it was. It's the thing I most dislike about the car, which I'm otherwise very pleased with.

Thank you, that's interesting because it's outside my experience.
I've always loathed diesel cars, so avoided them, and I've never had a turbocharger on any car I've owned, the last one had a supercharger which doesn't have the lag problem.

 

[Bletchleyite]

Thank you, that's interesting because it's outside my experience.
I've always loathed diesel cars, so avoided them, and I've never had a turbocharger on any car I've owned, the last one had a supercharger which doesn't have the lag problem.

I don't think I'd have another small engined diesel, and not only because they're falling out of favour. A large diesel (2.0+) is pleasant due to the high torque, e.g. the Ford 2.2Tdci in the Land Rover Defender I used to have despite it being a very heavy vehicle, the 1.5 in the Kuga needs the turbo spun up before it has any power or torque at all. Even when doing a hill start it's gutless, you need to rev it for a bit to spin the turbo up before moving off (which, to make it a bit easier, it does automatically when you hold on the clutch).

For a petrol, as large normally aspirated engines are falling out of favour there, I'd similarly go for one with a supercharger if possible.