Reducing the default urban road speed limit to 20 mph

[cactustwirly]

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.

That's incredibly poor driving advice. You should choose the gear based on the conditions and the ratios of the car (which is different for each gearbox)

I can be in 4th at 30 mph, and I'll be there all the way to 50 if I want to make progress.

1st gear is very fierce in my car so you just use it to move off, 2nd till 17mph, then 3rd to about 27 mph. I can be in 6th at 50 very happily.

Other cars will be completely different

I have stop start too - it's called "turning the key"

Mine doesn't have a key to turn

But then you lose the indicators and headlights...

 

[ABB125]

But then you loose the indicators and headlights...

Indicators? What are those?

 

[cactustwirly]

Indicators? What are those?

Didn't realise you drove a BMW, I apologise...

 

[ABB125]

Didn't realise you drove a BMW, I apologise...

(Un?)fortunately I don't...

Swerving back towards the topic of this thread, rather than reduce the speed limit why not simply ban all BMWs? That'll be far more effective at reducing the average speed along urban residential roads!

 

[miklcct]

That's incredibly poor driving advice. You should choose the gear based on the conditions and the ratios of the car (which is different for each gearbox)

I can be in 4th at 30 mph, and I'll be there all the way to 50 if I want to make progress.

1st gear is very fierce in my car so you just use it to move off, 2nd till 17mph, then 3rd to about 27 mph. I can be in 6th at 50 very happily.

Other cars will be completely different



Mine doesn't have a key to turn

But then you lose the indicators and headlights...

I may use wildly different gear even at the same speed.

For example, on a certain car with 6 gears, the car sometimes even prompt me to shift up when I'm using the 5th at 55 km/h. On a flat road maintaining a fixed speed I am happy to drive at the 6th, but at some situations requiring more control such as at curves, or at higher-risk locations I may stay at the 5th or even the 4th.

When the speed limit changes from 50 km/h to the rural national speed limit (90 km/h in a certain country). I may even downshift from 5th to the 3rd then ground-press the accelerator to reach the limit, then to the 6th directly.

When going downhill I choose a gear which can keep my car at my desired speed with the minimal use of brake or accelerator.

 

[Bletchleyite]

I hate those chicanes as they make traffic worse.
There's a hilarious one in reading. It caused both directions to become gridlocked as you couldn't pass the chicanes as the opposite side of the road had a queue for some traffic lights. So you have to wait for the traffic lights that you've just gone through to turn green before you can pass the chicane

That may actually be deliberate. I have come across a design in Bucks where traffic over a narrow bridge was, by virtue of positioning of give way lines, effectively controlled by a set of lights further up. If deliberate I think it quite clever.

Why is that a problem? Those who don't like others parking outside their own homes should be more considerate about where they themselves park.

Let's have a residents-only parking scheme, with incentives to use park and ride, for example?

I am happy for resident parking schemes IF they pay the market rate for the piece of land they are renting to exclusively park upon. I suspect if that were the case they would quickly all go away. If you want dedicated parking, buy or rent a house with it.

 

[bramling]

(Un?)fortunately I don't...

Swerving back towards the topic of this thread, rather than reduce the speed limit why not simply ban all BMWs? That'll be far more effective at reducing the average speed along urban residential roads!

The idea that BMWs are the evil of the road is rather outdated. Audi drivers are generally worse, and the one which slips under the radar is Range Rover. Round my way they are guaranteed to be the absolute worst by a mile.

 

[Bletchleyite]

That's incredibly poor driving advice. You should choose the gear based on the conditions and the ratios of the car (which is different for each gearbox)

It's been the case in every car I've owned, which for the record are:

1. Vauxhall Agila (badged Suzuki "Wagon R+") 1.2 petrol
2. Citroen Berlingo 1.4 petrol
3. Vauxhall Vectra-C 1.8VVTi estate
4. Land Rover Defender 110 County Station Wagon, 2.2Tdci
5. Ford Kuga 1.6 diesel (forget which specific engine it is)

Edit: Also alongside that a Land Rover Series 3 2.25 NA diesel, I forget which gears this liked, probably 4th for 30 as it was VERY torquey, and even with an overdrive (equivalent of 5th in a separate box) 50 was the most it'd do anyway.

That's a reasonably large set where the comfortable gear to easily do a given speed has been the first number of the limit (mostly). So I'm sticking with that view until I encounter a car where it's not the case. It seems to be the case in most 5-geared cars and some 6-geared ones.

Obviously things like hills and bends will result in the gear being changed down as necessary. If I go too high in the Kuga the turbo spins down and I get lag, which is quite annoying - I suspect this is true of many small turbodiesels which have little power without the turbo spun fully up.

For example, on a certain car with 6 gears, the car sometimes even prompt me to shift up when I'm using the 5th at 55 km/h.

In my experience these prompts result in labouring the engine and a loss of power and torque. They are set up purely as a contrived method of passing emissions tests and are best ignored. You bought a car with a manual gearbox for a reason, if you wanted the car to decide you'd buy an auto (and autos tend to be much more realistic than these prompts about when they change!)

When going downhill I choose a gear which can keep my car at my desired speed with the minimal use of brake or accelerator.

Surprises me how few people use engine braking, though it isn't very good on some (most notably diesel) vehicles.

 

[JamesT]

Surprises me how few people use engine braking, though it isn't very good on some (most notably diesel) vehicles.

When I was being taught in the late 90s engine braking was very much deprecated. Brakes are for braking, engines for making you go. You don't shift down sequentially whilst slowing down, but move down to an appropriate gear when you need to go again.

 

[Bletchleyite]

When I was being taught in the late 90s engine braking was very much deprecated. Brakes are for braking, engines for making you go. You don't shift down sequentially whilst slowing down, but move down to an appropriate gear when you need to go again.

I also learnt in the late 90s, and I think that isn't quite subtle enough, and if you didn't pick up the subtlety your instructor perhaps needs to change how they work. They did point out that you don't need to go down the gears to gain braking effect at each junction (like say my Mum does as she was taught). This was necessary on e.g. a Land Rover Series 3 I had years ago as the brakes were horribly weak. The reason not to do this is that unless you're very good at rev-matching you will wear the synchros with each change, and replacing them is expensive, whereas brake pads and discs are cheap to replace, probably the cheapest thing on the whole car. The other reason you used to do it was "crash boxes" where it'd be hard to get the gear again without stopping if you didn't do it.

However you definitely should, when descending a long hill, select and stay in an appropriate lower gear so you don't have to ride the brakes as much (though the effect varies by vehicle). If you fail to do this, they may overheat and you may lose some of your braking power when you most need it. Even the signage points this out! It happens less with all-round discs as most cars now have, but it does happen.

If your instructor didn't clearly point out the difference and why, then I would say they weren't very good.

 

[AlterEgo]

In my 1.2 petrol I'm in 4th gear as soon as I go above 30 and 5th gear from about 45. I've still not cracked what gear to be in for 20mph, neither 2nd or 3rd give very smooth rides.

Same with me - same engine size. Cars are designed to hold about 30mph, not 20. I can stick it in cruise at 20, but it is not a good ride and it tends to put you in third giving you not a huge amount of power if you do need it all of a sudden.

 

[Bletchleyite]

Same with me - same engine size. Cars are designed to hold about 30mph, not 20. I can stick it in cruise at 20, but it is not a good ride and it tends to put you in third giving you not a huge amount of power if you do need it all of a sudden.

Sounds like autos that can't nicely sit at 20 need a software update. If I put the manual limiter on to make it easier to control (20s aren't always suitable for cruise unless it is adaptive) my manual car does 20 quite happily, albeit in 2nd gear.

 

[Dai Corner]

Has any thought been given to the effects of extensive 20mph speed limits on the bus industry?

Urban buses may average less than 20 but they spend a lot of their time stopped either at bus stops, at junctions and traffic lights or in jams. They need to do 30 or more when they can to keep time.

 

[Bletchleyite]

Has any thought been given to the effects of extensive 20mph speed limits on the bus industry?

Urban buses may average less than 20 but they spend a lot of their time stopped either at bus stops, at junctions and traffic lights or in jams. They need to do 30 or more when they can to keep time.

I'm sure London provides plenty of evidence for this. The fix is probably to ensure they don't spend most of their time stopped by speeding boarding/alighting (tap in/tap out contactless and dual door) and by giving absolute priority at junctions and strategic use of bus lanes NOT shared with cyclists (there should be a separate segregated cycle facility).

 

[DelayRepay]

I'm sure London provides plenty of evidence for this. The fix is probably to ensure they don't spend most of their time stopped by speeding boarding/alighting (tap in/tap out contactless and dual door) and by giving absolute priority at junctions and strategic use of bus lanes NOT shared with cyclists (there should be a separate segregated cycle facility).

Also not shared with parked cars, delivery vans etc. In theory they shouldn't be but in practice I see little enforcement outside of London.

 

[Dai Corner]

I'm sure London provides plenty of evidence for this. The fix is probably to ensure they don't spend most of their time stopped by speeding boarding/alighting (tap in/tap out contactless and dual door) and by giving absolute priority at junctions and strategic use of bus lanes NOT shared with cyclists (there should be a separate segregated cycle facility).

The Welsh Government have funded tap-out devices, though they're not in use. My observations show that the vast majority of passengers are either concessionary pass holders or pay contactlessly. There is little or no budget for new dual door buses or infrastructure improvements as far as I'm aware.

Also not shared with parked cars, delivery vans etc. In theory they shouldn't be but in practice I see little enforcement outside of London.

I don't see much either.

 

[gg1]

Intelligent speed awareness (ISA)

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

Hopefully there will be a huge advance in the required technology between now and then.

My 2 year old Kia has one of the key features of ISA, a camera which can read speed limit signs, though in my case all it does is display them on the dashboard rather than reduce the speed accordingly.

There's one major issue though, it's not reliable. With regular speed limit signs the car detects a change in the limit roughly 80% of the time but with variable speed limit signs as is common on motorways reliability is down to closer to 30-40%. In addition when driving along a main road it occasionally picks up the speed limit signs on side roads or slip roads rather than the main roads, a recent example was when I was driving along a NSL grade separated dual carriageway a few weeks ago where the car incorrectly picked up the 30mph limit on a slip road. If this had been linked to an ISA system reducing my speed to that level would have been downright dangerous.

 

[DC1989]

Hopefully there will be a huge advance in the required technology between now and then.

My 2 year old Kia has one of the key features of ISA, a camera which can read speed limit signs, though in my case all it does is display them on the dashboard rather than reduce the speed accordingly.

There's one major issue though, it's not reliable. With regular speed limit signs the car detects a change in the limit roughly 80% of the time but with variable speed limit signs as is common on motorways reliability is down to closer to 30-40%. In addition when driving along a main road it occasionally picks up the speed limit signs on side roads or slip roads rather than the main roads, a recent example was when I was driving along a NSL grade separated dual carriageway a few weeks ago where the car incorrectly picked up the 30mph limit on a slip road. If this had been linked to an ISA system reducing my speed to that level would have been downright dangerous.

I think the new tech (Which is in all new models from this month, and all exisiting models from 2024) uses a combination of the camera and GPS

 

[gg1]

I think the new tech (Which is in all new models from this month, and all exisiting models from 2024) uses a combination of the camera and GPS

That would make sense for permanent speed limits, though a GPS wouldn't be any use for variable speed limit signs or temporary limits around roadworks.

 

[DC1989]

That would make sense for permanent speed limits, though a GPS wouldn't be any use for variable speed limit signs or temporary limits around roadworks.

Indeed - longer term (and I mean 2030+) I think there will need be a 'database' that any speed changes are inputted into by councils, contractors etc with start and end dates that feeds out to the cars.

 

[LSWR Cavalier]

The idea that BMWs are the evil of the road is rather outdated. Audi drivers are generally worse, and the one which slips under the radar is Range Rover. Round my way they are guaranteed to be the absolute worst by a mile.

Even simpler, young male drivers could be banned, that would be quite effective.

 

[Busaholic]

In my opinion we should be adopting a 25 mph speed limit in urban areas, to replace both 30 and 20 limits. It is common in US towns and cities apparently, and is obeyed much better in general than UK speed limits. We don't have to increase and decrease by 10mph steps. In France, you get 5kph variations, for instance on corners, whereas here you can be brought down from 60 mph to 30 in one go, which is crazy. There could still be 20 mph zones outside schools, for instance, but they should be exceptions. Enforcement should be far greater, but not pedantically - prosecuting drivers who touch 27 mph will only cause resentment.

 

[johncrossley]

and is obeyed much better in general than UK speed limits

I noticed the 25 mph limit being well observed in small American towns. A friend who was living there at the time said people stick to the limits because small towns are often heavily policed and so have little to do other than stop motorists.

 

[bramling]

Even simpler, young male drivers could be banned, that would be quite effective.

Again, round here one is *far* more likely to have issues with a baby-boomer in a Range Rover who has an inflated sense of self-importance / self-entitlement. There’s one round here who is so arrogant it’s almost a parody - early 60s, seems to think the rest of the world should literally bow down to him, never seen to leave his house on foot ever - utterly pathetic really.

 

[Bletchleyite]

Even simpler, young male drivers could be banned, that would be quite effective.

I have long thought that most adult things starting at 18 but driving at 17 was a bit incongruous. Upping that to 18 would no doubt have a significant safety effect, not just because of how much growing up one does in that year, but also because if you had to wait until 18 in reality most people going to uni would wait until they finished, thus taking the average age of starting driving up quite a bit.

 

[ABB125]

Even simpler, young male drivers could be banned, that would be quite effective.

Which is also sexist and ageist, not something we should be aiming for...

 

[Bald Rick]

The idea that BMWs are the evil of the road is rather outdated. Audi drivers are generally worse, and the one which slips under the radar is Range Rover. Round my way they are guaranteed to be the absolute worst by a mile.

by far the worst, in my experience, are those that drive Nissans.

 

[Hadders]

I have long thought that most adult things starting at 18 but driving at 17 was a bit incongruous. Upping that to 18 would no doubt have a significant safety effect, not just because of how much growing up one does in that year, but also because if you had to wait until 18 in reality most people going to uni would wait until they finished, thus taking the average age of starting driving up quite a bit.

Keep the age at 17 and many will have additional lessons from a parent while still living at home.

A year later and many are off to Uni, living away from home where all sorts of 'dodgy' learning practices are more likely to take place.

Also, anyone not at uni potentially needs a car 18 to get to work.

 

[bluenoxid]

The whole learning to drive and testing would benefit from a review, including consideration on starting age (some schools of thought suggest a reduction to 16) and a limit on engine size/acceleration rate.

I believe that one of the prompts for this should be the introduction of E-Scooters, where an even lower age for a speed controlled device would be reasonable.

 

[Bletchleyite]

The whole learning to drive and testing would benefit from a review, including consideration on starting age (some schools of thought suggest a reduction to 16) and a limit on engine size/acceleration rate.

I believe that one of the prompts for this should be the introduction of E-Scooters, where an even lower age for a speed controlled device would be reasonable.

Speed limited e-scooters just need to be considered the same as e-bikes, which have no age limit at all.