20mph Speed Limits
Discussion
20mph limit is more dangerous but too costly to reverse, council admits
However, I do remember reading - over the years - articles / editorials and such like that predicted 20mph zones increasing the accident rates in a given area. Based on the Telegraph story above, it seems that there may be some mileage to that argument.
I should, perhaps, do some sleuthing to see if any similar reports or information are available on the 20 limit areas in Newport and Oakengates but was wondering on the effects - good or bad - of them on others who have to drive through them on a day-to-day basis.
Article said:
Bath and North East Somerset Council spent £871,000 bringing in the 13 new speed zones just 12 months ago. But one year on, a report has found that the rate of people killed or seriously injured has gone up in seven out of the 13 new 20mph zones.
This is just one example from one Local Authority, so not an exhaustive "forensic" examination of the efficacy of 20mph speed limits. I'm not exactly familiar with them either, having just two 20mph areas nearby.However, I do remember reading - over the years - articles / editorials and such like that predicted 20mph zones increasing the accident rates in a given area. Based on the Telegraph story above, it seems that there may be some mileage to that argument.
I should, perhaps, do some sleuthing to see if any similar reports or information are available on the 20 limit areas in Newport and Oakengates but was wondering on the effects - good or bad - of them on others who have to drive through them on a day-to-day basis.
Oxford has numerous 20 MPH limits. The biggest issues? Cyclists going down hills at over 20 MPH, as well as, traveling close enough to the 20 limit that overtaking them is near impossible.
This leads to a build up of cars doing 15 MPH behind them. Anyone who has lived or driven in Oxford will know how many cyclists are on the road - especially term times and summer.
Note: I’m not blaming cyclists for this or saying they get in the way. It’s simply hard to get past them quickly and safely when they’re almost at the speed limit or over.
This leads to a build up of cars doing 15 MPH behind them. Anyone who has lived or driven in Oxford will know how many cyclists are on the road - especially term times and summer.
Note: I’m not blaming cyclists for this or saying they get in the way. It’s simply hard to get past them quickly and safely when they’re almost at the speed limit or over.
Stu08 said:
Oxford has numerous 20 MPH limits. The biggest issues? Cyclists going down hills at over 20 MPH, as well as, traveling close enough to the 20 limit that overtaking them is near impossible.
This leads to a build up of cars doing 15 MPH behind them. Anyone who has lived or driven in Oxford will know how many cyclists are on the road - especially term times and summer.
Note: I’m not blaming cyclists for this or saying they get in the way. It’s simply hard to get past them quickly and safely when they’re almost at the speed limit or over.
if they're doing 20mph why are you only doing 15? and if they're at or near the limit why do you want to overtake them?This leads to a build up of cars doing 15 MPH behind them. Anyone who has lived or driven in Oxford will know how many cyclists are on the road - especially term times and summer.
Note: I’m not blaming cyclists for this or saying they get in the way. It’s simply hard to get past them quickly and safely when they’re almost at the speed limit or over.
cherryowen said:
However, I do remember reading - over the years - articles / editorials and such like that predicted 20mph zones increasing the accident rates in a given area. Based on the Telegraph story above, it seems that there may be some mileage to that argument.
Portsmouth 20 the best you could say was that the results were mixedThe accident stats over a number of years have shown the increase in accidents in 20s over the other limits
Government says to local authorities be careful where you put them - really they only want them where its going to improve safety
Who is it that is promoting them?
ktard.Move on, we can't make any judgements from the limited information in that article. It states that in seven out of thirteen areas that introduced measures, accident rates involving injury or death went up in the following twelve months. So in six areas they must have fallen or at least not changed. That leaves several questions that must be answered before attempting to conclude that 20mph limits don't work:
(1) by how much did accident rates go up in each area? If in each case they went up from say 4 to 5 that's probably well within the boundaries of statistical chance and reflects random variation, especially if the year before they were introduced accident rates were relatively low to begin with.
(2) by how much did accident rates go down in the 6 out of 13 areas where they fell? Did they go down so much that the net effect across all 13 areas was an overall reduction in accidents?
(3) what has happened to traffic speeds in the areas where accident rates didn't fall? I live in a recently designated 20mph area of Birmingham and I've seen not a shred of evidence that anybody is acting on the signs. Traffic plows on at 30-35mph regardless, and the intermittent nutter shoots by at easily 50. If accident rates aren't falling, maybe signs alone aren't enough to bring speeds down. There is plenty of evidence from other areas including Hull that shows that when speeds are reduced to 20mph in residential areas, injury rates and fatalities fall.
(1) by how much did accident rates go up in each area? If in each case they went up from say 4 to 5 that's probably well within the boundaries of statistical chance and reflects random variation, especially if the year before they were introduced accident rates were relatively low to begin with.
(2) by how much did accident rates go down in the 6 out of 13 areas where they fell? Did they go down so much that the net effect across all 13 areas was an overall reduction in accidents?
(3) what has happened to traffic speeds in the areas where accident rates didn't fall? I live in a recently designated 20mph area of Birmingham and I've seen not a shred of evidence that anybody is acting on the signs. Traffic plows on at 30-35mph regardless, and the intermittent nutter shoots by at easily 50. If accident rates aren't falling, maybe signs alone aren't enough to bring speeds down. There is plenty of evidence from other areas including Hull that shows that when speeds are reduced to 20mph in residential areas, injury rates and fatalities fall.
Chromegrill said:
Move on, we can't make any judgements from the limited information in that article. It states that in seven out of thirteen areas that introduced measures, accident rates involving injury or death went up in the following twelve months. So in six areas they must have fallen or at least not changed. That leaves several questions that must be answered before attempting to conclude that 20mph limits don't work
Fair points all. Chromegrill said:
(1) by how much did accident rates go up in each area? If in each case they went up from say 4 to 5 that's probably well within the boundaries of statistical chance and reflects random variation, especially if the year before they were introduced accident rates were relatively low to begin with.
Personally, I'd not be interested in how much accident rates went up in a given area; just that they went up when the sole reason for implementing a 20 limit was to reduce accidents. By the same reasoning, if accident rates increased (by any percentage) in a 50mph limit, said limit would usually argued to be lowered. Chromegrill said:
(2) by how much did accident rates go down in the 6 out of 13 areas where they fell? Did they go down so much that the net effect across all 13 areas was an overall reduction in accidents?
Good question. Further and better information definitely required.Chromegrill said:
(3) what has happened to traffic speeds in the areas where accident rates didn't fall? I live in a recently designated 20mph area of Birmingham and I've seen not a shred of evidence that anybody is acting on the signs. Traffic plows on at 30-35mph regardless, and the intermittent nutter shoots by at easily 50. If accident rates aren't falling, maybe signs alone aren't enough to bring speeds down. There is plenty of evidence from other areas including Hull that shows that when speeds are reduced to 20mph in residential areas, injury rates and fatalities fall.
I suppose this boils down to how your "average" driver perceives the validity of a given speed limit reduction. As an example, nearby is a section of the A5 (single carriageway) that was - some years ago - reduced to a 50 limit. Now, in the many years prior to that not one thing on or near to the section of road in question had changed. Nothing. As such, prevailing conditions permitting, I've never adhered to that "new" 50 limit as it is clearly pointless. Chromegrill said:
Move on, we can't make any judgements from the limited information in that article. It states that in seven out of thirteen areas that introduced measures, accident rates involving injury or death went up in the following twelve months. So in six areas they must have fallen or at least not changed. That leaves several questions that must be answered before attempting to conclude that 20mph limits don't work:
it's already been answered by DfT and the statsPut a 20 limit in the right place accidents reduce, the wrong place they increase
Blanket ones can be the worst as they'll likely include some of each
Theres no magic put in a twenty and things'll be universally safer
The research from UK and Europe typically shows:
- 20mph "zone" (with speed bumps) = reduces injuries and deaths by 30-80%...
- 20mph "limit" (without speed bumps) = reduces injuries and deaths by 10-30%...
Yipper said:
The research from UK and Europe typically shows:
Sauce?- 20mph "zone" (with speed bumps) = reduces injuries and deaths by 30-80%...
- 20mph "limit" (without speed bumps) = reduces injuries and deaths by 10-30%...
Also, what's the difference between a 20 "zone" and a 20 "limit"?
(just interested for review purposes, really)
kiethton said:
Lewisham has done it, only a few people actually obey it = queue of cars overtaking a socialist/learner/granny akin to a milk float, often dangerously.
Just put it back to 30mph ffs.
I commute through there, and it is absolutely chaotic. Almost everyday, I witness people doing 20mph being tailgated going up/down this hill. Surely this is more dangerous?Just put it back to 30mph ffs.
cherryowen said:
Yipper said:
The research from UK and Europe typically shows:
Sauce?- 20mph "zone" (with speed bumps) = reduces injuries and deaths by 30-80%...
- 20mph "limit" (without speed bumps) = reduces injuries and deaths by 10-30%...
Also, what's the difference between a 20 "zone" and a 20 "limit"?
(just interested for review purposes, really)
As above, a zone has physical measures to reduce speed, like a big hump. A limit just has a sign telling you to slow to 20.
https://www.rospa.com/rospaweb/docs/advice-service...
Eyersey1234 said:
Cherryowen, was the A5 known as a bad road for accidents before the speed limit was lowered to 50? I ask because the A1079 in Yorkshire had a number of serious accidents before the limit was reduced to 50mph for a section between Hayton and Wilberfoss.
Nah, the section I'm on about is about half a mile in length from the Priorslee island to just past the turning for the tip.Like I said, for years and years it was NSL with no issues whatsoever and overnight it was changed to a 50.
BTW, thanks for the link Yipper. I'll have a look at that.
Stu08 said:
keirik said:
if they're doing 20mph why are you only doing 15? and if they're at or near the limit why do you want to overtake them?
You’re that guy aren’t you.
Edited by anonymous-user on Sunday 17th December 21:49
No, I think that you’re ‘that guy’. Hard to understand any issue with bycycles travelling at or near the limit, or why it would cause cars to travel 5mph slower than them.
REALIST123 said:
Stu08 said:
keirik said:
if they're doing 20mph why are you only doing 15? and if they're at or near the limit why do you want to overtake them?
You’re that guy aren’t you.
Edited by Stu08 on Sunday 17th December 21:49
No, I think that you’re ‘that guy’. Hard to understand any issue with bycycles travelling at or near the limit, or why it would cause cars to travel 5mph slower than them.
Bikes will never be travelling at exactly 20mph, changing gradients/hills, potholes, manhole covers and fitness will see to that. Likewise cars will sit an an indicated 20, a real 17/18. Between the 2, with overtaking opportunities in some urban environments being a little challenging (keep lefts, junctions etc.) I can see why average traffic speeds would be reduced to ~15mph
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