Surely this is what you would expect isnt it

[bazwillrun]

http://www.thesun.co....g-in-20mph-zones.html

If you increase the amount of roads with 20 as the limit then there are bound to be more accidents on them as a statistic if you reduce the amount of roads where 30 is the limit.

surely the figure should show how many accidents were on those roads before they became 20mph zones and then compare the two

[Gromit]

It is what you would expect from the Sun. Misleading

// How many people died or were injured on roads with a 30 mph speed limit then? The Sun doesn’t say, but the official data is easy enough to find. In 2010, 127,377 people were killed or injured on a road with a 30 mph speed limit. In 2011, it was 125,494.

In other words, that “1% drop” corresponds to almost 2000 fewer people were injured on 30 mph roads, while 400 more people were injured on 20 mph roads. That is a net decrease of 1448 injuries/deaths.

Just looking at the number of injuries on 20 mph roads is not going to tell you about how effective 20 mph speed limits are. You have to compare them with other speed limits. Data about how many 20 mph zones there are is hard to find, which makes making sense of the Sun‘s data difficult, but it certainly looks like a lot of them have been springing up lately, so an increase in injuries is to be expected – if there are more roads, there will always be more accidents! //

[jno]

quite right, both - inadequate statistics.

[Gromit]

Road deaths 2011

20mph zone - 7
30mph zone - 636

To present thses figures as 20mph zones are not working is very disingenuous.

The full stats are here.

http://www.dft.gov.uk...tics/tables/ras30006/

[pdq1]

To drive at 20mph you need to drop down a gear. In a lower gear you have much more acceleration. Together with the lower speed limit they usually install humps. So a driver is constantly reducing his speed to 10mph and accelerate once over the hump which causes acccidents.

[eyethenkyew]

It ain't the speed limits which create problems, it's the idiots behind the wheel who put the boot down even in 20mph zones - I should know, I live in close proximity to a road meant to be just that but which is regularly ignored by speeding drivers, some hammering along at around 60mph.

[jake-the-peg]

Well here's some statistics for you not from the Sun

I used to be quite behind speed cameras until I started looking into it in a bit more detail and found out some surprising stuff

The Government's "It's 30 for a reason" campaign was based on data from 1979 - over 30 years old!

http://www.roadsafetygb.org.uk/news/1191.html

In fact if you go and look at the most recent data the probability of killing someone in an accident at 40 is now roughly what it was at 30 in 1979

Interesting point 2

In 2009 Swindon shut off all their speed cameras and put big hoods over them saying "Not in use"

The 2010 statistics are now available

http://www.wiltshire....alty-joint-report.pdf

Guess what accident figures have continued to decline at the same rate as they had before.



But the thing that's particularly interesting in the above report is the breakdown on what such an accident costs the council

Here we're peeking behind the curtain - the motivation to reduce accidents is driven by that to reduce costs.

The idea is that by using speed cameras you'll achieve that

That logic doesn't seem to hold water in the Sun's report - or in the Swindon experience.

I will need to find the actual report the Sun's story - you need to find the actual numbers but accident rates have been declining so if 20mph areas were working you'd at least expect to see them stay static.

These sort of things can be very counter intuitive for example it may well be that the 20mph areas are giving people a false sense of security on the roads which is leading to more accidents.

I think someone needs to take a long hard look at road safety policy based on the actual up to date numbers (rather than on what people think is "obvious") and make some changes.

It's also worth bearing in mind that the UK has just about the best road safety record on the whole planet

[jno]

jake, as I recall there was some suggestion a few years ago that the best way to reduce accidents was to remove signage altogether, so drivers would have to slow down. Even traffic lights give a "false sense of security" as drivers expect pedestrians to cross there and pedestrians expect drivers to pay special care there - the corollary being that they would pay less care elsewhere. Now the'd have to be fully attentive everywhere.

They seem to be trying such a mixed zone by the V&A in London. I don't know how it's working.

All "targets" will be random (like "reducing accidents by 50%"). That doesn't make them a bad thing. Fewer people die in crashes at 40mph than they used to because "emergency medical procedures have improved"? I don't know how much that would gladden my heart if I was in one.

[factor-fiction]

The fact that most people now wear seat belts may also be a factor in why "Fewer people die in crashes at 40mph than they used to "