Road safety: UK set to adopt vehicle speed limiters

[mauvais]

Induced demand is real, but Cid is right: noone is going to be tipped into significant behavioural change (e.g. no car <-> car, or even train vs car commuting) by marginal changes in cost or convenience.

 

[UnderOpenSky]

Well, whenever new motorways were built to get rid of congestion they swiftly filled up with drivers keen to take advantage of the improved roads. I don't think it's too much of a stretch to suggest that if speeds were increased on motorways, more people would seek to take advantage of it.



New roads create new traffic

Be a bit pointless building roads if they didn't expect demand for them. Lovely as they would be to drive.

 

[mauvais]

Be a bit pointless building roads if they didn't expect demand for them. Lovely as they would be to drive.

The point is that instead of merely relieving existing demand on other roads - e.g. building a bypass that intends to take traffic off urban roads - it (usually unintentionally) produces new journeys that didn't previously exist.

 

[Sasaferrato]

So, again, make the entire network average speed enforced.

When I was in Berlin, pre the wall coming down, there was a two hour minimum transit time for the 106 miles of the corridor. An American schoolteacher misheard, and though it was two hours max. She came through in 58 minutes in her Transam. I was in Checkpoint Alpha when she came in. As she was a civvy, she got a bollocking and that was that. Had it been me, I would have been in deep shit.

 

[bellaozzydog]

I had a hire carhyundai a couple of weeks ago.
It had lane assist control on it.

I drive cautiously and react very early to stuff with lane changes

I almost crashed overreacting to the cars response as I gently moved across a lane on a dual carriage way

It feels as if someone has grabbed your steering wheel and shook it in the opposite dir3vtion to travel. I shit myself.

All this clever shit gets switched off (that stop start engine stuff freaks me out as well) when i’m driving temp cars/hires. I’m sure i’d Get used to it in the end with regular use.

I haven’t read the whole 5hread buti’m Presuming the car boy clarkson wannabes ar3 out in strength

 

[editor]

The point is that instead of merely relieving existing demand on other roads - e.g. building a bypass that intends to take traffic off urban roads - it (usually unintentionally) produces new journeys that didn't previously exist.

Exactly.

Induced demand – related to latent demand and generated demand – is the phenomenon that after supply increases, more of a good is consumed. This is entirely consistent with the economic theory of supply and demand; however, this idea has become important in the debate over the expansion of transportation systems, and is often used as an argument against increasing roadway traffic capacity as a cure for congestion. This phenomenon, called induced traffic, is a contributing factor to urban sprawl. City planner Jeff Speck has called induced demand "the great intellectual black hole in city planning, the one professional certainty that everyone thoughtful seems to acknowledge, yet almost no one is willing to act upon."
Induced demand - Wikipedia

In the UK, the idea of induced traffic was used as a grounds for protests against government policy of road construction in the 1970s, 1980s and early 1990s, until it became accepted as a given by the government as a result of their own Standing Advisory Committee on Trunk Road Assessment (SACTRA) study of 1994.[20] However, despite the concept of induced traffic now being accepted, it is not always taken into consideration in planning.

Induced demand - Wikipedia

 

[stavros]

The point is that instead of merely relieving existing demand on other roads - e.g. building a bypass that intends to take traffic off urban roads - it (usually unintentionally) produces new journeys that didn't previously exist.

I believe some limited studies have been done in the opposite direction, that is, when capacity is reduced. Whereas increased capacity induces greater net traffic movements, decreasing the existing capacity, for example for a bus lane, decreases the net number of movements. The study I looked at, which I can't find currently, also took into account alternative routes to the affected section in its conclusion.

ETA: I found it, from UCL, dated 21 years ago: Evidence of the effects of road capacity reduction on traffic levels - UCL Discovery

 

[mauvais]

I believe some limited studies have been done in the opposite direction, that is, when capacity is reduced. Whereas increased capacity induces greater net traffic movements, decreasing the existing capacity, for example for a bus lane, decreases the net number of movements. The study I looked at, which I can't find currently, also took into account alternative routes to the affected section in its conclusion.

Wouldn't surprise me. Supposedly lots of people turn down well-paid jobs in Manchester because of the perpetual roadworks of recent times, and lots of people were either fired or quit during the Southern Rail debacle a year or two back.

 

[stavros]

Wouldn't surprise me. Supposedly lots of people turn down well-paid jobs in Manchester because of the perpetual roadworks of recent times, and lots of people were either fired or quit during the Southern Rail debacle a year or two back.

I don't know Manchester, but I believe Andy Burnham's headline target as mayor is to improve the sustainable transport provision. Are the major employment sites not served well by public transport?

Sorry for the partial thread, ahem, derailment.

 

[T & P]

Oh come on. You're going right over the top here. Why on earth would anyone need to disable speed-limiters to "stay alive"?

Needing a short burst of increased speed to get out of a potentially dangerous situation is not an uncommon scenario at all, and many drivers will experience it at some point.

A classic example would be realising mid-way while overtaking a long vehicle that you have misjudged how much time you had available to complete the manoeuvre. Sometimes braking to get back behind the lorry you were trying to overtake is the best and safest option, but other times completing the overtake is the safest option, and the limiter kicking in then and denying the driver an extra 15-20 mph for a few moments could prove disastrous in some situations.

If the limiters were to be designed to allow a one-off speed increase request for a short period of time, then this issue would be solved. But being able to use a little extra speed can and indeed does make certain much situations safer.

 

[editor]

Needing a short burst of increased speed to get out of a potentially dangerous situation is not an uncommon scenario at all, and many drivers will experience it at some point.

And from the article linked in the OP that this entire thread is based on:

The system can be overridden temporarily. If a car is overtaking a lorry on a motorway and enters a lower speed-limit area, the driver can push down hard on the accelerator to complete the manoeuvre.

 

[UnderOpenSky]

Kind of like driving an automatic. I think it would be a great reminder, especially for town driving.

 

[T & P]

And from the article linked in the OP that this entire thread is based on:

That’s great news. I was not arguing against the implementation of limiters btw, but pointing out that needing a bit of extra speed to make a situation safer can be absolutely true.

Not saying you were implying the same of course, but I still remember a discussion in the transport forum years ago in which someone told me ‘accelerating out of trouble’ as they described it was 100% bollocks and could never really happen simply because the Highway Code didn’t account for it

 

[mauvais]

And from the article linked in the OP that this entire thread is based on:

If you did drive, you'd probably have run into situations where this doesn't work in practice.

Not so long ago I pulled over on a joining sliproad hard shoulder because I ran into and then couldn't disengage the speed limiter (set to 30) quickly enough. I know what I'm doing in a car, and there are four different ways to disengage my particular one - two buttons, a switch and the kickdown - but it was too much to process in a short space of time, so aborting was probably the right call in that moment.

I've forgotten the limiter whilst overtaking too and whilst that particular scenario has never led to a near-miss for me, it's definitely not ideal.

Someone will probably come to harm from this thing, but in fairness it needs to be weighed against the benefit too.

 

[pseudonarcissus]

I rather like the idea of a cruise control that adjusts to the prevailing limit...that’s how I’m imagining it.

 

[Saul Goodman]

Well, whenever new motorways were built to get rid of congestion they swiftly filled up with drivers keen to take advantage of the improved roads. I don't think it's too much of a stretch to suggest that if speeds were increased on motorways, more people would seek to take advantage of it.



New roads create new traffic

Are you suggesting people would go out and pass the driving test and buy a car, because the speed limit increased?

 

[editor]

Are you suggesting people would go out and pass the driving test and buy a car, because the speed limit increased?

No. Any more stupid questions?

 

[editor]

If you did drive, you'd probably have run into situations where this doesn't work in practice.

Not so long ago I pulled over on a joining sliproad hard shoulder because I ran into and then couldn't disengage the speed limiter (set to 30) quickly enough. I know what I'm doing in a car, and there are four different ways to disengage my particular one - two buttons, a switch and the kickdown - but it was too much to process in a short space of time, so aborting was probably the right call in that moment.

But that's not what is being proposed.

 

[mauvais]

But that's not what is being proposed.

Yes it is. You'll disable it either with some on/off toggle or with kickdown, just as it is on my car. But neither necessarily works well when you have to react quickly.

 

[editor]

Yes it is. You'll disable it either with some on/off toggle or with kickdown, just as it is on my car. But neither necessarily works well when you have to react quickly.

Exactly where does it say that?

 

[mauvais]

Exactly where does it say that?

In the article text that you quoted?

 

[editor]

In the article text that you quoted?

Where does it mention toggles?

 

[mauvais]

Where does it mention toggles?

The whole system can be disabled, read the original story in the OP.

It's exactly as speed limiters (with or without ISA) work today.

 

[editor]

The whole system can be disabled, read the original story in the OP.

It's exactly as speed limiters (with or without ISA) work today.

Toggles?

 

[mauvais]

Toggles?

For fuck's sake.

You tell us how it'll be turned off then, oh wise one.

 

[editor]

For fuck's sake.

You tell us how it'll be turned off then, oh wise one.

Err...

The system can be overridden temporarily. If a car is overtaking a lorry on a motorway and enters a lower speed-limit area, the driver can push down hard on the accelerator to complete the manoeuvre.

Not a toggle in sight.

 

[mauvais]

Yes, that's the kickdown bit, very good.

Now read the article in the OP that you started.

A full on/off switch for the system is also envisaged, but this would lapse every time the vehicle is restarted.

Like every car that has oooooone.

 

[editor]

Yes, that's the kickdown bit, very good.

Now read the article in the OP that you started.

Like every car that has oooooone.

So why you would struggle so hard to push down on an accelerator, and where would these toggles come into the moment? And more importantly, if it's all as wildly dangerous as you make out, how come it's getting so much support from the European Transport Safety Council, the AA and other organisations? Is there something wrong with your foot?

However, the new system as it's currently envisaged will not force drivers to slow down. It is there to encourage them to do so, and to make them aware of what the limit is, but it can be overridden. Much like the cruise control in many current cars will hold a particular speed, or prevent you exceeding it, until you stamp on the accelerator.

The EU says the plan could help avoid 140,000 serious injuries by 2038 and aims ultimately to cut road deaths to zero by 2050.

 

[mauvais]

So why you would struggle so hard to push down on an accelerator, and where would these toggles come into the moment? And more importantly, if it's all as wildly dangerous as you make out, how come it's getting so much support from the European Transport Safety Council, the AA and other organisations?

For the reasons I already explained

It takes a moment to work out why your car won't accelerate as expected and another to decide what to do about it. Some situations like merging or overtaking already have a high cognitive load and this will therefore be problematic.

 

[editor]

For the reasons I already explained

It takes a moment to work out why your car won't accelerate as expected and another to decide what to do about it. Some situations like merging or overtaking already have a high cognitive load and this will therefore be problematic.

...assuming you'd forgotten that you had the limiter onboard. Doh!

But so everyone who is recommending this system is wrong, in your opinion, yes?