Suitable speed limit for minor country roads

pwa
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Re: Suitable speed limit for minor country roads

Postby pwa » 6 Jun 2018, 12:59pm

Richard Fairhurst wrote:I see your point thirdcrank, but I think that ship has sailed. Many drivers treat NSL as a target speed too. I don't see that installing 30 roundels in place of NSL roundels would cause that sort of driver to speed up: they already drive as fast as they can.

mjr's allusion to technology is interesting, though. Already, satnavs/Google Maps/etc. know about speed limits and use it in route choice. If a road has a 20mph limit, that makes it less likely that a satnav will choose it (because the overall speed will be slower), thereby reducing rat-running. Looking into the future, that will surely be even more important as self-driving cars come into use. (And it may not be that far in the future: there was an interesting paper in the US last month about self-driving cars being feasible on rural roads even without detailed lane mapping databases.)


The idea of reducing speed limits on certain lanes to stop satnavs choosing them is very interesting. I can't see why that wouldn't work.

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Re: Suitable speed limit for minor country roads

Postby thirdcrank » 6 Jun 2018, 1:28pm

Richard Fairhurst wrote:I see your point thirdcrank, but I think that ship has sailed. Many drivers treat NSL as a target speed too. I don't see that installing 30 roundels in place of NSL roundels would cause that sort of driver to speed up: they already drive as fast as they can. ...


I'm not talking about "that sort of driver" but rather the people who generally drive quite reasonably but who might see a posted number as a target in the sense that it seems officially approved for that particular road. People intent on driving as fast as they can get away with will do so, as we know from the numbers snapped by prominent speed cameras.

At the moment, "driver assist" technology is developing rapidly, perhaps as part of the rush to driverless, but there are already systems to alert a driver to being too close to the vehicle in front and to apply the brakes to prevent or mitigate a collision. I could imagine it's feasible to have something similar for blind bends. Just like real corners, you never really know what's round the corner in technology and even less whether it will be adopted or ignored. When road-pricing was on the agenda, I was predicting that satnav's would be programmable to avoid it.

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Re: Suitable speed limit for minor country roads

Postby Richard Fairhurst » 6 Jun 2018, 1:38pm

pwa wrote:The idea of reducing speed limits on certain lanes to stop satnavs choosing them is very interesting. I can't see why that wouldn't work.


We're actively pursuing it in our little Cotswold town. There's a wide B-road round the edge, and narrow historic streets in the centre. At present, satnavs often direct commuters to the railway station via the narrow streets (TomTom and HERE both do this; Google uses the B-road; with OSM it depends on the routing engine). Our hope is that a 20mph limit will sway the weightings such that they all go round the B-road instead.
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Re: Suitable speed limit for minor country roads

Postby Bmblbzzz » 6 Jun 2018, 2:39pm

thirdcrank wrote:At the moment, "driver assist" technology is developing rapidly, perhaps as part of the rush to driverless, but there are already systems to alert a driver to being too close to the vehicle in front and to apply the brakes to prevent or mitigate a collision. I could imagine it's feasible to have something similar for blind bends. Just like real corners, you never really know what's round the corner in technology and even less whether it will be adopted or ignored. When road-pricing was on the agenda, I was predicting that satnav's would be programmable to avoid it.

OT really, but I'd say it's more of a crawl or slide to driverless vehicles. That is, we'll eventually arrive at fully autonomous vehicles through a gradual process of ever greater driver assistance and automation of individual tasks, rather than dramatic leaps or attempted leaps such as we see from Google and Uber. Perhaps.

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Re: Suitable speed limit for minor country roads

Postby horizon » 6 Jun 2018, 3:17pm

thirdcrank wrote:
I'm not talking about "that sort of driver" but rather the people who generally drive quite reasonably but who might see a posted number as a target in the sense that it seems officially approved for that particular road. People intent on driving as fast as they can get away with will do so, as we know from the numbers snapped by prominent speed cameras.



If you drive through most villages today (30 mph zones) you will undoubtedly see a small turning off down some half forgotten muddy lane glorified with a two huge No Speed Limit signs. I think a blanket NSL on unclassified roads of 30 mph would actually send the right signal. I do appreciate what you are saying, so it wouldn't be a panacea but still a big message IMV.
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Re: Suitable speed limit for minor country roads

Postby Bmblbzzz » 6 Jun 2018, 3:34pm

For some - actually quite a lot of - drivers, there is a thrill to be had in breaking the speed limit for its own sake, regardless of the actual speed you're doing. Breaking a low limit is less dangerous and antisocial than breaking a high limit but delivers that thrill.

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Re: Suitable speed limit for minor country roads

Postby mjr » 6 Jun 2018, 3:45pm

reohn2 wrote:The thing is that speeding along any such roads saves only miniscule amounts of time a few seconds at most and most being only a race to the next TL to sit in a jam more often than not.

Not necessarily. There are two villages near me which are 6km apart by a straight C-class road, part of which is 30mph limit but as soon as the houses end, it's 60mph limit although the road surface does not quite permit that without risking an abrupt detour into a tree. To use much better A/B roads between them is 9km but takes 1 minute longer - so of course, almost everyone uses the C road. 1 minute doesn't seem much but that's on a 7 minute journey, so it's significant. This is probably reproduced on a larger scale across the county.

Of course, there's an argument that that C road should be a B road and it's at least as good geographically as many nearby B roads, but years of C-class maintenance would make reclassification and remediation rather expensive, which I suspect is much of the reason it remains a C road.

And of course, it's pretty much no-go for all except the bravest cyclists for most of the day. It's been a long time since I rode it in the daylight. There are other C/U roads which are about 2km longer and far quieter and less stressful.
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Re: Suitable speed limit for minor country roads

Postby AlaninWales » 6 Jun 2018, 4:11pm

pwa wrote:
Richard Fairhurst wrote:I see your point thirdcrank, but I think that ship has sailed. Many drivers treat NSL as a target speed too. I don't see that installing 30 roundels in place of NSL roundels would cause that sort of driver to speed up: they already drive as fast as they can.

mjr's allusion to technology is interesting, though. Already, satnavs/Google Maps/etc. know about speed limits and use it in route choice. If a road has a 20mph limit, that makes it less likely that a satnav will choose it (because the overall speed will be slower), thereby reducing rat-running. Looking into the future, that will surely be even more important as self-driving cars come into use. (And it may not be that far in the future: there was an interesting paper in the US last month about self-driving cars being feasible on rural roads even without detailed lane mapping databases.)


The idea of reducing speed limits on certain lanes to stop satnavs choosing them is very interesting. I can't see why that wouldn't work.

I can. Satnavs are frequently years behind re. what speed limits are on which roads (even when they get it right). This is for all sorts of reasons, whether the data the makers use is or isn't updated regularly, through to whether the Satnav can or is, updated with changed data. Whether it's my built-in cat satnav, supplied with wrong information (which for local roads I know was wrong when the car was new two years ago) or my separate Garmin with lifetime updates, which when updated still has speed limits wrong.

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Re: Suitable speed limit for minor country roads

Postby reohn2 » 6 Jun 2018, 4:42pm

Richard Fairhurst wrote:
pwa wrote:The idea of reducing speed limits on certain lanes to stop satnavs choosing them is very interesting. I can't see why that wouldn't work.


We're actively pursuing it in our little Cotswold town. There's a wide B-road round the edge, and narrow historic streets in the centre. At present, satnavs often direct commuters to the railway station via the narrow streets (TomTom and HERE both do this; Google uses the B-road; with OSM it depends on the routing engine). Our hope is that a 20mph limit will sway the weightings such that they all go round the B-road instead.

The only snag is,commuters who use the route regularly will already know the fastest route and use it.
Unless those 20mph limits are policed those commuters will ignore the 20 limit as they do in my locale.
Last edited by reohn2 on 6 Jun 2018, 5:00pm, edited 1 time in total.
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Re: Suitable speed limit for minor country roads

Postby reohn2 » 6 Jun 2018, 4:47pm

Bmblbzzz wrote:
thirdcrank wrote:At the moment, "driver assist" technology is developing rapidly, perhaps as part of the rush to driverless, but there are already systems to alert a driver to being too close to the vehicle in front and to apply the brakes to prevent or mitigate a collision. I could imagine it's feasible to have something similar for blind bends. Just like real corners, you never really know what's round the corner in technology and even less whether it will be adopted or ignored. When road-pricing was on the agenda, I was predicting that satnav's would be programmable to avoid it.

OT really, but I'd say it's more of a crawl or slide to driverless vehicles. That is, we'll eventually arrive at fully autonomous vehicles through a gradual process of ever greater driver assistance and automation of individual tasks, rather than dramatic leaps or attempted leaps such as we see from Google and Uber. Perhaps.

Itll be a looonnnggg time before that kind of technology is used in all vehicles and until then the there'll be a lot of frustrated MGIF drivers trying to get past legal driving auto driven cars.I can see it being a rare old time in some areas,unless theres a real threat of prosecution.
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Re: Suitable speed limit for minor country roads

Postby Richard Fairhurst » 6 Jun 2018, 4:48pm

You'd be surprised! A few months ago I spoke to a driver headed for the station who was going through the centre of town, and had been held up by the bin lorry in front. I asked why she didn't go round the B-road. Her answer was "because of the speed bumps". Those speed bumps were taken out about 10 years ago...

(But yes, some enforcement is clearly desirable.)
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reohn2
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Re: Suitable speed limit for minor country roads

Postby reohn2 » 6 Jun 2018, 4:58pm

mjr wrote:
reohn2 wrote:The thing is that speeding along any such roads saves only miniscule amounts of time a few seconds at most and most being only a race to the next TL to sit in a jam more often than not.

Not necessarily. There are two villages near me which are 6km apart by a straight C-class road, part of which is 30mph limit but as soon as the houses end, it's 60mph limit although the road surface does not quite permit that without risking an abrupt detour into a tree. To use much better A/B roads between them is 9km but takes 1 minute longer - so of course, almost everyone uses the C road. 1 minute doesn't seem much but that's on a 7 minute journey, so it's significant. This is probably reproduced on a larger scale across the county.

Of course, there's an argument that that C road should be a B road and it's at least as good geographically as many nearby B roads, but years of C-class maintenance would make reclassification and remediation rather expensive, which I suspect is much of the reason it remains a C road.

And of course, it's pretty much no-go for all except the bravest cyclists for most of the day. It's been a long time since I rode it in the daylight. There are other C/U roads which are about 2km longer and far quieter and less stressful.

There are very few C class roads in my area that are so straight,I can only think of one OTTOMH and that one has speed bumps on it.
IMO we have to face the fact that there are some lunatics in charge of motor vehicles who need bring to book with penalties to match and unless that line is followed they'll remain as lunatics.
Once it's realised that speeding costs dearly and that there's a very real chance of being caught nothing will change,as things stand the loonies know there's very little chance of being caught anyway and even if they collide with another vehicle unless someone is injured it's just an insurance job :?
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Re: Suitable speed limit for minor country roads

Postby Steady rider » 19 Jun 2018, 1:44pm

http://www.brake.org.uk/rsw/15-facts-a- ... ntry-roads

Speed on country roads - Brake the road safety charity

http://www.brake.org.uk

More than half (51%) of fatal crashes in Britain occur on country roads [1]. Per mile travelled, country roads are the most dangerous roads for all kinds of road user [2]:


https://assets.publishing.service.gov.u ... 1-2013.pdf

parts 126/127 mention 'vulnerable road users.'

Setting local speed limits - assets.publishing.service.gov.uk

assets.publishing.service.gov.uk

Department for Transport Department for Transport Circular 01/2013 . SETTING LOCAL SPEED LIMITS . CONTENTS . 1. Introduction 2. Background and objectives of the Circular


Details from 1995 publication 'Safer Cycling'.

Test data from vehicles impacting dummies at lower speeds indicate a reduction in HIC (Head Injury Criterion) value of 78% for cyclists and 70% for pedestrians. This is due to reduced impact speeds from 40 to 30 km/hr, which could result from a change in driving speed of 4.15km (2.6mph) when reaction and braking times are included.

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The utility cyclist
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Re: Suitable speed limit for minor country roads

Postby The utility cyclist » 19 Jun 2018, 2:43pm

Surely we should apply the HC rule of going at a speed you can stop well within the distance you can see to be clear, in most cases this would mean the vast majority of B, C, unclassified roads being 40mph or less and IMHO 40mph should be the default national speed limit with GPS systems in all motorvehicles with transponders in signpost to ensure that the maximum speeds are not exceeded. This should be the one thing that takes precedence over any other safety measure.

Many a time I've driven on the motorway at circa 60mph constant, usually averaging 55mph (as my then 155 mile each way trip had only 6 miles of non trunk/motorway), not only does this allow you more thinking time, it conserves a significant proportion of fuel and from that lower amounts of pollutants and the time 'lost' even over a fairly long journey is not significant IMHO. You arrive more relaxed and to achieve say a 65mph average I'd have to be going at 75-80mph most of the time.
On shorter journeys on B and C roads the time saving by allowing vehicles to go 50/60mph over 30/40mph is tiny, and yet the increase in incident increases massively, particularly on roads that have limited sight lines for whatever reason or less width of the carriageway than would be seen on an urban road yet we would generally have 30mph limit there.

That the government have not done anything at all with regards to speed limits and slashed them drastically on all roads except the motorways (which should be far more heavily policed anyway, makes them complicit in the deaths and serious injuries sustained by so many including people on bikes. Why are they not seriously looking at changing speed limits on all roads as a matter of national emergency, this would save far more lives than the ridiculously overt reaction/spend to so called terrorist attacks, yet the terrorism on the roads are literally killing and maiming every single day.

Their failure to eradicate the harm done and inaction to take steps to protect is unlawful by definition IMHO, particularly when we know the results of the inaction and what happens when you do act to restrict those that kill/maim with impunity.

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Re: Suitable speed limit for minor country roads

Postby Steady rider » 19 Jun 2018, 3:03pm

https://en.wikipedia.org/wiki/List_of_c ... death_rate

The UK rate is 2.9 and relatively low by world standards. Speed is one important aspect.

if 2 drivers are approaching on a long bend, they may each be able to see say 70m and at 40 mph they may need about 72m to stop in, 36 m each. So I assume in some circumstances you may need more than your seeing distance to be able to stop safely, because the other driver may be doing say 50 mph or more.

ps
Reports have detailed the cycling fatality risk with rates varying per billion kilometres cycled, for example the Netherlands with a rate of 8, Germany 11, France 27, United Kingdom 21 and United States of America 49.

So action to improve safety for cyclists is needed - 3% of total transport spending for 10 years, £570 million per year.
(The UK spends about 22 times more on overseas aid)
https://www.ukpublicspending.co.uk/uk_t ... ng_60.html