Balanced story on 20mph limits

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marinyork

Resting in suspended Animation
Location
Logopolis
My house in Leeds is surrounded by one of these residential 20mph zones! Does it mean safer slower roads? NO!

Out of interest how big is this zone? I've lived in and near a 20mph zone before and the problem in my view is that usually they are too small.
 
Wow! why bother to research when you already know the answer instictively?

Particularly when careful research gets the 'wrong' answer.
I don't instinctively know any answer. It's called daily 1st hand experience. No report will ever beat that for arriving at conclusions!

That's because the London example was enforced by passive speed restraints (principally humps). Sticking up 20 mph signs a 20 mph zone does not make.
I completely agree with this! My arguement goes further. Sticking speed humps in the middle of the road doesn't a 20mph zone make either. Drivers just straddle them at their original speed making it more dangerous for cyclists (for example) as we have to move to the left to get round them - and motorists have to do the same to straddle them! If you're going to use speed restraints they have to be the ones that cover the full width of the road and not the cheapo humps!!
 

benb

Evidence based cyclist
Location
Epsom
I don't instinctively know any answer. It's called daily 1st hand experience. No report will ever beat that for arriving at conclusions!

Rot. It was "daily 1st hand experience" that led most people to conclude that the sun went round the earth.
Appearances can be deceptive, and our intuition is often wrong.
 

marzjennings

Legendary Member
Do these 20mph limits also impact cyclists?

Trying to think why it's so different over here in the US. In my neighbourhood there are no white lines, no speed bumps, no Give way or Stop signs no speed limit signs. Kids play ball games in the street. Almost everyone drives way less than 30 (which I think is the limit). I think one of the reasons is that many neighhoods as designed NOT to be through ways. There's usually only one or two entry points to the neighourhoods, where they'll be stop signs or lights, but usually no rat runs or short cuts to other parts of town.

I remember living on street in Reading that was blocked off at one end to traffic, so no through traffic an in general a quiet street. Yes it was a pain sometimes to drive in the wrong direction to connect to a through road, but it kept the road quieter than a neighbouring street which while having the same speed limit was always busy. Could more 'neighbourhooding' of streets help more than blanket 20mph limits?
 
I think one of the reasons is that many neighhoods as designed NOT to be through ways. There's usually only one or two entry points to the neighourhoods, where they'll be stop signs or lights, but usually no rat runs or short cuts to other parts of town.
That's the main reason for speeding in residential areas over here (in my opinion again - I know there are some tempremental people out there :whistle: !!!) . Main roads have contraflows, speed bumps etc.. so people in a rush use estates as "rat runs" (we've ALL done it!!) Nobody sensible would object to travelling at a reduced speed (20mph say) in the estates as long as the main roads connecting the estates remained at 30mph, free flowing and free from council tampering!!

We could always be really radical and bring back the old "Tufty Club/Green Cross Man" and tackle the problem from both sides instead of just blaming the drivers all the time too!!!

I doubt I'm the only one who's had a pedestrian just step out in front of them without looking. Or is that my fault too :biggrin:
 

benb

Evidence based cyclist
Location
Epsom
Everyone is entitled to their opinion. Maybe you should ride the same 20mph zone that I do and see if yours remains the same!

You're entitled to your own opinion, of course, but you're not entitled to your own facts.

Anecdote != evidence.
 
Anecdote != evidence.
And neither do statistics fortunately!
 

benb

Evidence based cyclist
Location
Epsom
And neither do statistics fortunately!

What? So clinical trials showing a statistically significant benefit to a treatment doesn't count in your book, to pick just one example of where statistics are extremely useful evidence.
 

Dan B

Disengaged member
A statistic is (or should be) a mathematically defensible summary of an awful lot of evidence (the raw data). The data collected and the manner of summarising are in each case open to challenge, but if you dismiss the whole field because you don't understand it, that says more about you than about the people publishing them
 

StuartG

slower but no further
Location
SE London
I don't instinctively know any answer. It's called daily 1st hand experience. No report will ever beat that for arriving at conclusions!

Galileo & Copernicus were wrong too then ... you are seriously debunking carefully and extensively researched evidence on the basis of personal experience? But then I guess on the same basis you would debunk all the scientific evidence that personal experience and common sense are not always right ...

I had preconceptions about speed humps and cameras being dangerous in their own right. However, the more you research it - them more 'gut instinct' is found to be wanting ...

Take care.
 
What? So clinical trials showing a statistically significant benefit to a treatment doesn't count in your book, to pick just one example of where statistics are extremely useful evidence.
Please re-read the original article. I believe 'trend' and 'average' are statistical terms! You can't tell me stats prove speed bumps are a good thing when they clearly show that can't be proved in the case of Portsmouth! For example - maybe they work in London because the bumps are only every 400m apart - whist in Portsmouth they're 800m. So a sweeping generalisation like (Speed bumps save lives- is ,excuse my English, a load of bull!).

Statistics are, and always will be a guide to a course of action - but not the be all and end all. Without a set of control conditions they are next to useless (medical trials use strict control conditions btw - good example to prove my point). I could also counter with examples of obviously idiotic statistical logic!! By all means, use statistics for this purpose, then do some on the ground work to actually see if they're accurate.

In the case of the zone where I live - the generalisation isn't true - as is also the case in Portsmouth apparently. No point in shooting the messenger just because the message isn't the one you want to hear!!:hello:
 

benb

Evidence based cyclist
Location
Epsom
Please re-read the original article. I believe 'trend' and 'average' are statistical terms! You can't tell me stats prove speed bumps are a good thing when they clearly show that can't be proved in the case of Portsmouth! For example - maybe they work in London because the bumps are only every 400m apart - whist in Portsmouth they're 800m. So a sweeping generalisation like (Speed bumps save lives- is ,excuse my English, a load of bull!).

Statistics are, and always will be a guide to a course of action - but not the be all and end all. Without a set of control conditions they are next to useless (medical trials use strict control conditions btw - good example to prove my point). I could also counter with examples of obviously idiotic statistical logic!! By all means, use statistics for this purpose, then do some on the ground work to actually see if they're accurate.

In the case of the zone where I live - the generalisation isn't true - as is also the case in Portsmouth apparently. No point in shooting the messenger just because the message isn't the one you want to hear!!:hello:

Nice way to rewrite history. You said statistics are not evidence. That is bull. It's obvious you can't take evidence from one situation and apply it to another, different situation, and I never said you could.

I also never said that all speed bumps everywhere save lives. What definitely does save lives is significantly lowering the speed of traffic, no matter how you go about achieving that.
 
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