20 MPH speed limit across london in three years

[detective-boy]

I've no idea where you're getting these figures from (some pro-motoring organisation, I assume), but as a resident of this city, I don't want cars racing down residential streets at 40mph.

And I'd be obliged if you stopped trying to project your - or someone's else's - definition of a 'residential street' onto me. And since when was most residential traffic business related?

If you're referring to the "about 50%", nowhere. I just applied a bit of logic: if today a delivery could be made at 30mph and tomorrow it had to be made at 20mph it'd take about 50% as long again meaning an approximate 50% increase in cost (primarily of staff hours).

And you assume wrong. I have no fucking idea at all what any "pro-motoring organisation" thinks.

And I'm not "projecting" anyone's definition of residential street on to you. I'm simply giving words their normal meaning - a "street" in which people "reside". If you want them to mean something else, perhaps you'd care to share that with us.

 

[citydreams]

As I understand it, that is pretty much exactly what they're suggesting - editor certainly is in relation to "residential roads".

No, the suggestions are for setting the speed limit at 20mph unless a good case can be made for varying the speed on a link. This is similiar in approach to having 30 mph except for where 20mph zones can be argued for isn't it? Except in this case, the balance of power resides with residents, for a change.

Incidentally, the TLRN has been split up into 1km sections, each managed individually. So there is no reason against having a 20mph in residential areas, then allowing an increase in speed where driving conditions allow.

 

[detective-boy]

I'm very much in favour of variable speed limits on some roads to allow a higher limit at certain times of day whilst restricting it at others.

We agree then.

But we're in a tiny minority - blanket reduced limits are the current weapon of choice in the "War on Speeding".

 

[detective-boy]

... then allowing an increase in speed where driving conditions allow.

The point is that "driving conditions" vary for any number of reasons other than simple location.

And applying fixed limits removes the need for people to think. Automaton driving is not good driving and this approach, in my view, encourages it.

 

[citydreams]

Just that all those examples - and dozens more - could be justified on the same basis as the "everyone should drive at 20mph cos if you go any faster people will get hurt if you crash" argument which was being espoused..

They may be justified, but they're not practical. Reducing the speed limit is. Besides which, this isn't a discussion about fitting lights on the motorway. You're being unnecessarily obtuse.

 

[citydreams]

Applying fixed limits removes the need for people to think..

What rubbish. Where's the evidence for this?

 

[beeboo]

I believe that reasonable limits on all sorts of activity should be set and that people should then be responsible for their own actions. And that if that means there are some "acceptable casualties" then so be it. A riskless society would be fucking boring.

A riskless society might be boring, but a society where RTAs are one of the main causes of death amongst young people, kids are prevented from playing outside due to the dangers of roads and people of all ages are fearful of cycling isn't a barrel of laughs either.

We're not talking about cycle helmets where the risk is to the individual, when you're driving the main risk is to other road users, not yourself. That's not 'nannying' really is it?

 

[editor]

If you're referring to the "about 50%", nowhere. I just applied a bit of logic: if today a delivery could be made at 30mph and tomorrow it had to be made at 20mph it'd take about 50% as long again meaning an approximate 50% increase in cost (primarily of staff hours).

If you're going to make claims about a colossal economic penalty being brought about by reducing residential road speeds, please produce a credible source because I can't be arsed to waste time debating meaningless figures you've just made up in your head.

 

[editor]

And applying fixed limits removes the need for people to think. Automaton driving is not good driving and this approach, in my view, encourages it.

And that's even dafter than your made up figures claiming that the economy might collapse because motorists were being forced to reduce speeds in residential areas.

I normally value your input on these boards, and appreciate your insights into police procedures and the law, but you're really spouting some stupendously silly hyperbolic bollocks here.

 

[Sigmund Fraud]

If you're referring to the "about 50%", nowhere. I just applied a bit of logic: if today a delivery could be made at 30mph and tomorrow it had to be made at 20mph it'd take about 50% as long again meaning an approximate 50% increase in cost (primarily of staff hours).

This would hold true on an empty road with no junctions or traffic lights. What a glibly simplistic analysis of traffic movement! Perhaps if we applied your logic and upped the speed limit to 60mph we'd have halve costs! Of course! Its so simple

 

[T & P]

Although technically they all might residential streets, for the purpose of this discussion I consider residential streets those which are not 'trunk roads', high streets and 'major' distribution routes within a city.

Pretty much those roads that are not coloured in your average street atlas actually:

Now I'd be prepared to see a reduction to 20mph in those steets that are not coloured (my traditional view of 'residential' streets) but it'd be lunacy and completely unjustified to lower the limits on the coloured roads.

Is that a fair compromise for everyone?

 

[detective-boy]

What rubbish. Where's the evidence for this?

Fuckwits ad nauseum claiming it couldn't possibly be their fault because they were only doing 29mph ... and utterly missing the point that the speed limit is NOT the safe speed at all times.

 

[detective-boy]

We're not talking about cycle helmets where the risk is to the individual, when you're driving the main risk is to other road users, not yourself. That's not 'nannying' really is it?

And your answer to the other points where the main risk is to others is ...

 

[detective-boy]

Is that a fair compromise for everyone?

Although the vast majority of non-coloured roads would be entirely appropriate for 20mph limits there are a significant number (e.g. Loughborough Road) which are secondary routes where it would be neither appropriate nor necessary, and certainly not at all hours of the day.

 

[detective-boy]

Perhaps if we applied your logic and upped the speed limit to 60mph we'd have halve costs! Of course! Its so simple

No. 60mph would be unsafe on the majority of urban roads at most times (the exception being dual-carriageways and major trunk routes, at least at night).

 

[detective-boy]

I normally value your input on these boards, and appreciate your insights into police procedures and the law, but you're really spouting some stupendously silly hyperbolic bollocks here.

There is stupendously silly hyperbole from the "(Only) Speed Kills" brigade. I have no desire to allow a free-for-all on the roads. Quite the contrary, I would like to see far better enforcement of genuinely dangerous speeding offences and other dangerous driving (most of which is entirely ignored if it can't be done with a fucking camera).

But the current enforcement regime is entirely counterproductive and will simply NOT solve the problem. In exactly the same way that the current enforcement regime against drug offences is entirely counterproductive and will simply NOT solve the problem.

Would you be arguing for equivalent enforcement in that sphere ...

 

[editor]

There is stupendously silly hyperbole from the "(Only) Speed Kills" brigade.

What's that got to do with my points?

 

[Sigmund Fraud]

No. 60mph would be unsafe on the majority of urban roads at most times (the exception being dual-carriageways and major trunk routes, at least at night).

Er, I know that.

I'm just pointing out that your basic maths extrapolation is incredibly simplistic and not real world. Halving or doubling doesn't offer the same fractional reduction in cost or increase in time.

And as you know, costs don't work on nice simple sliding scales like that - you would first have to prove that your delivery drivers average speed over the day would be less; as central Londons average speed is 10mph that might be very hard and a 20mph limit would be just as academic as 30mph.

You might equally find the delivery drivers route could be done quicker if everybody had a 20mph maximum.

 

[Mr T]

Incidentally, the TLRN has been split up into 1km sections, each managed individually. So there is no reason against having a 20mph in residential areas, then allowing an increase in speed where driving conditions allow.

Not sure where you heard this from, but its not the case AFAIK (I work in TfL Streets).

 

[citydreams]

Not sure where you heard this from, but its not the case AFAIK (I work in TfL Streets).

Who do you work for? It's part of the new Network Management Plan.

ps. I guess we'll be sharing a building soon

 

[citydreams]

Who do you work for?

I think introducing a default 20mph limit across London would probably be incompatible with the Traffic Management Act 2004

Ah, think I've just worked it out. Is he ridiculously tall and still waiting for his medal of honour?

 

[detective-boy]

Er, I know that.

I'm just pointing out that your basic maths extrapolation is incredibly simplistic and not real world. Halving or doubling doesn't offer the same fractional reduction in cost or increase in time.

And as you know, costs don't work on nice simple sliding scales like that - you would first have to prove that your delivery drivers average speed over the day would be less; as central Londons average speed is 10mph that might be very hard and a 20mph limit would be just as academic as 30mph.

You might equally find the delivery drivers route could be done quicker if everybody had a 20mph maximum.

Er, I know that.

But I would suggest that my broad conclusion that lower speed limits would increase delivery times and, hence, costs would be far, far more logical that that they would either remain the same or fall. Especially bearing in mind that a lot is done (post, milk, newspapers ...) outside normal rush hours, at times when even in "residential" roads 20mph is unnecessary and would certainly be way slower than they achieve now.

 

[detective-boy]

What's that got to do with my points?

There are other posts and points of view. Not everything is aimed personally and exclusively at you and yours. You were referring to my posts as "stupendously silly hyperbole" when that could only be justified if you were linking them with other's, more extreme, points of view.

 

[newbie]

Is there any evidence to show how fuel consumption/airborne pollution/noise might be affected by altering speed limits?

 

[Sigmund Fraud]

Er, I know that.

But I would suggest that my broad conclusion that lower speed limits would increase delivery times and, hence, costs would be far, far more logical that that they would either remain the same or fall. Especially bearing in mind that a lot is done (post, milk, newspapers ...) outside normal rush hours, at times when even in "residential" roads 20mph is unnecessary and would certainly be way slower than they achieve now.

But a theoretical average of 30mph can't be reached now - central London daytime average is 10.5mph - what you're failing to grasp (perhaps deliberately) is that 20mph can't be reached either...it can just about be reached in the middle of the night, there are two many junctions and sets of lights for the drop to really matter.

And what makes you so certain that speeds would be 'way slower'? have you run any kind of modelling of traffic flows? I'd wager Tfl have.

 

[goldenecitrone]

How do they "try to drive over speed bumps"?

Do they not succeed in doing so? How do cars "rear"???! I don't understand this manoeuvre that you are describing?

Giles..

Car comes towards speed bumps in road. To avoid slowing down when they drive over the speed bump they rear (or swerve) over to the right so that their wheels pass on either side of the bump and they don't have to slow down. However this takes them into the oncoming lane and directly into my path. Which pisses me off.

 

[Mr T]

Ah, think I've just worked it out. Is he ridiculously tall and still waiting for his medal of honour?

no i work in RND. are you coming to the exhibition tomorrow?

 

[detective-boy]

And what makes you so certain that speeds would be 'way slower'? have you run any kind of modelling of traffic flows? I'd wager Tfl have.

I have eyes.

No traffic travels at 20mph at present, most doesn't travel at 30mph at quiet times when there are no hazards. Why invent something that (a) won't be complied with and (b) won't be enforced? If we properly enforced the current 30mph limit in "residential streets" then we would vastly improve things. What makes the "(Only) Speed Kills" brigade think that sticking up lotys of shiny new 20mph signs will magically lead to speeds being reduced. They are deluded.

(And I was not talking about AVERAGE speeds, I was talking about speeds achieved when moving between junctions and traffic lights and such like ... because the speed limit applies at each and every point in time, not over the whole journey (as clearly you know but, for some reason, you choose to ignore))

 

[Sigmund Fraud]

I have eyes.
(And I was not talking about AVERAGE speeds, I was talking about speeds achieved when moving between junctions and traffic lights and such like ... because the speed limit applies at each and every point in time, not over the whole journey (as clearly you know but, for some reason, you choose to ignore))

So tell me Detective-boy, when you drive to a destination which matters most: How long it took you or what was the fastest speed you could achieve on the way?

Its the average speed that matters - I would have expected you to know that.

 

[beeboo]

What makes the "(Only) Speed Kills" brigade think that sticking up lotys of shiny new 20mph signs will magically lead to speeds being reduced. They are deluded.

Research undertaken for TfL analysing the impact of 20mph zones suggests that speeds were reduced by 9mph and accidents reduced by about 50% of more compared with before the speed limits were introduced.

There is some evidence to suggest that some traffic was 'displaced' elsewhere but not enought to account for the drop in accidents, and didn't conclude that accident rates had risen elsewhere.

http://www.tfl.gov.uk/assets/downloads/corporate/ResearchSummaryNo2_20mphZones.pdf

(And I was not talking about AVERAGE speeds, I was talking about speeds achieved when moving between junctions and traffic lights and such like ... because the speed limit applies at each and every point in time, not over the whole journey (as clearly you know but, for some reason, you choose to ignore))

pft, you referred to the time taken to move stuff about rising by 50% at least, you just seem to be backpeddling now.