Confusing Speed Limit Signs

[lozc]

Virtually all the arguments advanced here for 20mph limits could also be advanced for 15, 10, or even 5mph.

The reality is that a compromise must be struck somewhere. The only absolutely safe roads would have no moving traffic on them at all.

Whatever people's views on the limit, my main concern currently is the conflicting and confusing signage, meaning that all the limits are widely ignored.

[mako]

Well said Lozc

[rodneybewes]

lozc Wrote:

-------------------------------------------------------

> Virtually all the arguments advanced here for

> 20mph limits could also be advanced for 15, 10, or

> even 5mph.

> The reality is that a compromise must be struck

> somewhere. The only absolutely safe roads would

> have no moving traffic on them at all.

>

> Whatever people's views on the limit, my main

> concern currently is the conflicting and confusing

> signage, meaning that all the limits are widely

> ignored.

True, there's nothing worse than it not being clear where the changes are. I doubt it's any consolation but it won't be long before the whole whack is 20mph.

[James Barber]

at council assembly last week it was announced that the 20mph policy is costing ?450,000 to introdunce the signs - publicity, pre traffic speed monitoring (44 locations in Dulwich area)

That before 12 months are up speeds will be recorded and then ?792,000 spent on physical measures where speed are higher than 20mph. I suspect that will hardly touch the sides for the speeds people are still travelling at but a start.

[Charles Notice]

What a waste of money.

Sure the money could be spent better elsewhere.

Why have you suddenly produced this news?

[rodneybewes]

James Barber Wrote:

-------------------------------------------------------

> at council assembly last week it was announced

> that the 20mph policy is costing ?450,000 to

> introdunce the signs - publicity, pre traffic

> speed monitoring (44 locations in Dulwich area)

> That before 12 months are up speeds will be

> recorded and then ?792,000 spent on physical

> measures where speed are higher than 20mph. I

> suspect that will hardly touch the sides for the

> speeds people are still travelling at but a start.

Thanks for that James, I think that is very positive news.

[Charles Notice]

Can we know where the 44 locations are and why they have been selected. Council officers choice,residents, cycle pressure groups or expensive consultants.

[dbboy]

What a total waste of ?1.25M of TAX PAYERS money. In a time when councils are struggling to make savings and balance the books the council can waste this amount of money, truly unbelievable and sheer incompetence. Councillors you should ALL hang your heads in SHAME and resign!!!!!

[Blah Blah]

Pursuasive data there Bawdy-nan, I have to admit. But I still feel the compromise was in making residential roads 20mph and keeping main roads at 30, although during peak times many of them move slower than that. That in turn, as someone has pointed out above, was the incentive to stay off the residential roads, whereas now?

There's nothing wrong with spending money where it makes sense to. So accident spots, junctions, outside schools etc. One of the worst design features has been the sinusoidal road humps, which are ineffective at slowing many vehicles and tend to crumble at the edges, requiring regular and costly maintenance.

I'm sure some of my feelings on the subject come from the fatigue of constant moves to change the rules of our roads. Whatever happened to 'drive according to the conditions' for example?

There was another thread recently regarding a lady who was knocked down at the junction of ED Grove and LL. It has made me look at that junction since and there's no doubt that the crossing installed to make pedestrian crossing safer on LL has made the traffic turning right off LL less cautious when those lights are on red. So road planners don't get things right all of the time.

[richard tudor]

Charles Notice Wrote:

-------------------------------------------------------

> Can we know where the 44 locations are and why

> they have been selected. Council officers

> choice,residents, cycle pressure groups or

> expensive consultants.

After the Townley Road who did what show I too would like to know the answers to the above.

The answers are there as they made a decision based on them

[wulfhound]

Virtually all the arguments advanced here for 20mph limits could also be advanced for 15, 10, or even 5mph.

The reality is that a compromise must be struck somewhere. The only absolutely safe roads would have no moving traffic on them at all.

Not really. The arguments for 20 are only strong because of its very minimal impact on most Inner London journey times. 20 greatly reduces mortality in collisions involving cars (when compared to 30), but even 10mph won't do that for collisions involving lorries.

What a waste of money.

Sure the money could be spent better elsewhere.

We'll have to agree to disagree. The net savings from reduced injury rate are likely to be significant.

Pursuasive data there Bawdy-nan, I have to admit. But I still feel the compromise was in making residential roads 20mph and keeping main roads at 30, although during peak times many of them move slower than that. That in turn, as someone has pointed out above, was the incentive to stay off the residential roads, whereas now?

I started off thinking that as well. A few things that changed my mind:

- CrashMap data ( http://crashmap.co.uk/Search ), the majority of the problem is on the major roads. Seems sensible to apply the remedy where the problem is greatest.

- Traffic count data e.g. http://www.southwark.gov.uk/downloads/download/3056/transport_data which shows that, however much we might wish it to be otherwise, there is no clear distinction in traffic volume between main and minor roads in the area. Lordship Lane is plainly a main road, but how about Dulwich Village? Court Lane?

- The main roads tend to be high streets as well, with lots of pedestrians. So *some* bits of main road should probably be 20 for that reason. Near schools there's a strong case for it too. At that point you end up with a confusing, piecemeal patchwork, the very complaint which started this thread. Much better to have a clear, area-wide policy.

- As an anti rat-running measure it again seems persuasive at first to have the split, but at the times when most of the rat-running happens, the average (not peak) speed on the main roads is below 20 anyway. You still save time by taking short cuts, even at 20. To make much of a dent in peak time rat running would require a much lower limit again, not something that's likely to happen.

[mako]

What a complete waste of money. absolutely disgraceful. after the monitoring is up perhaps it should be considered why in some areas limits will be exceeded. For example because conditions make it sensible to rather than because of perceived dangerous driving.

[christgill]

I noticed this morning that the top of Eynella Road (from the junction with Woodwarde Road to Lordship Lane (40 yards?)) is a 30mph zone.

[mako]

Wulfhound. You state the arguments for twenty are only strong because of the very minimal impact on journey times. Yet the only way in which it can have minimal impacts on journey times is if it has minimal impacts on speeds in which case it is a pointless waste of money. A limit 50% higher is obviously not minimal but a huge difference.

[mako]

Wulf are you also claiming that traffic accidents in southwark cost 15million a year? If so what are these costs?

[bawdy-nan]

Re increased journey times: the estimated increase in journey times is 10-25 seconds per mile (evidence from central Bristol cited in the Edinburgh 20mph fact sheet)

[LadyNorwood]

Croxted Road is 20mph; then increases to 30mph as you cross the South Circular; then reverts to 20mph on Croxted Road - what a complete and utter waste of resources and time for a 10 yard stretch of tarmac....

[Pickle]

I drove up from Honor Oak Station towards ED last night at 9pm, at 20mph. The person behind me became so impatient he overtook on a blind corner and came very close to a head on collision with a bus. Aggressive overtaking has also happened on Sydenham Hill on a Sunday morning. I am all for 20 mph on side streets, but on the main roads it does feel ridiculously slow and is at risk of causing accidents due to the impatience of people not wanting to drive so slow.

[StraferJack]

"due to the impatience of people not wanting to drive so slow"

aka criminal activity

[Blah Blah]

Pickle makes a good point though. There is nothing and no-one to enforce these speed limits. And wreckless overtaking will be the result. Hard enough getting all drivers to stick to 30mph.

[wulfhound]

Wulfhound. You state the arguments for twenty are only strong because of the very minimal impact on journey times. Yet the only way in which it can have minimal impacts on journey times is if it has minimal impacts on speeds in which case it is a pointless waste of money. A limit 50% higher is obviously not minimal but a huge difference.

Think about it - most of our journey *time* (as opposed to *distance*) driving in Inner London is spent waiting at lights, or queuing in slow moving traffic (unless you do most of your driving after 8pm ish). The journey time average speed for driving in London during the day is about 12mph, and has been for years. So there's an average speed and a peak speed. Bringing the peak down doesn't affect the average by much at all, but it does greatly reduce the likelihood of *severe* collisions, which, for cars/vans/taxis, tend to occur at or near peak speed.

The figure quoted by bawdy-nan (10-25 seconds per mile) suggests 2 minutes on a 6 mile journey - 32 minutes instead of 30. Journey time *reliability* actually *improves*, because the worse-than-average journeys are affected less than better-than-average.

If so what are these costs?

I'm basing on DfT figures, which are approx as follows:

Fatal accident - ?1.7m

Serious injury - ?200k (AFAIK this means injury requiring at least an overnight stay in hospital)

Slight injury - ?15k (injury requiring hospital treatment but not overnight stay)

( see https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/244913/rrcgb2012-02.pdf for how they figured it out - it appears to have been prepared by civil servants with no particular axe to grind, not lobbyists )

These figures are averages - individual cases will vary enormously.

And LB Southwark STATS19 (police road casualty data) for 2013:

Fatal: 5

Serious: 82

Slight: 905

... which in fact yields a much larger number than ?15m. No doubt these figures are debatable, but I think they help get a handle on the scale of the problem.

Croxted Road is 20mph; then increases to 30mph as you cross the South Circular; then reverts to 20mph on Croxted Road - what a complete and utter waste of resources and time for a 10 yard stretch of tarmac....

Because the South Circular is a Red Route, i.e. it's regulated by TfL not LB Southwark. TfL has decided that the limit on Red Routes should stay 30 for the time being.. you'd have to be pretty brave to try and cross that anywhere apart from a designated crossing, and they've legalised cycling on the pavement along most of it, so it probably makes sense for it to stay 30.

[Pickle]

Yes, criminal activity, but how to do anything about it?

[Penguin68]

I think the most cogent argument is simply that impacts at around 20mph (vehicle to stationary body) cause less damage (to people and other vehicles) than impacts at 30mpg - so deaths move to serious injury, serious injury to less so. As vehicles get larger and heavier (think how small saloon cars were in the 1950s compared with now) the inertia of the impacts are anyway increasing, so reducing speed restores some balance. Whoever is to blame in an accident, slower speeds allow greater reaction and response times - substantially so when vehicles are closing at a combined 40mph rather than 60mph (modern crumple zones mean that vehicle on vehicle impacts are less likely to lead to death and serious injury to those in the vehicles).

The actual reduction in journey time at a maximum 20mph rather than 30mph for most journeys through Southwark is, frankly, immaterial.

The problem lies in the poor and confusing signage which means that individuals frequently do not know what the relevant limit is where they are - which is exacerbated by boy racers and white-van men who hoot first and think (if at all) a great deal later.

[StraferJack]

"but how to do anything about it?"

more pointedly - how do to anything about without people screaming "cash cow!!!"

[bobbsy]

All this stuff about average speeds in London being sub 20mph is probably true. But these figures apply to all London, and will be skewed enormously by central central London figures. We are talking about Dulwich roads, which are not as congested as the city centre. 30mph is a sensible limit for main thoroughfares, especially outside peak hours. But very very few people observe the 20mph limit. I ride into town almost every day, and am constantly tailgated even at 30mph. And, as I have pointed out before, the residential road I live ojn has been 20mph for a long time, and hardly anyone observes that.

Money would have been much better spent on other projects.

Bring back weekly refuse collection I say.