Safe Speed Forums

Hi all,

I obtained some data from the Strathclyde camera partnership in response to my request for accident causations at camera sites (1999-2004). The cameras were installed in 2003. Interesting to see what actually caused the accidents. In their wisdom they have attributed some of the causations to speed but neglected too say to fast for the prevailing conditions (see the very bottom of report).

ACCIDENT CAUSATIONS


Below are the primary causes noted on the police report for accidents occurring at each camera site in Inverclyde. The figure beside each cause shows the total number of accidents attributed to each cause. These figures are for all accidents at the Inverclyde camera sites from 1st January 1999 to 31st December 2004.

Please note – There is often more than one cause involved in a road accident. Until 2005, when a road accident report was produced, only one primary causation code was noted. So if a drunk driver was driving in wet weather going above the speed limit and crashed round a left hand bend, either one of these factors could have been recorded as the primary cause. Therefore, the causes below show only the primary causations and do not fully represent every cause involved in these accidents. The road accident report has been changed in 2005 to now allow more than one causation code to be listed.

All safety camera sites are selected in consultation with local road managers and traffic management police. Local knowledge of accidents and the factors that led to them is crucial in determining whether excessive speed is a prevalent contributor and whether a camera is an appropriate solution. It should be noted that all possible road engineering improvements and other measures must be considered before safety camera operation is recommended.



A8 East Hamilton Street

Making a right turn manoeuvre 10
Failing to maintain a safe distance 9
Emerging carelessly from a side road 3
Changing lane without ascertaining that road is clear 2
Pedestrian crossing carelessly 2
Losing control – other manoeuvre 1
Criminal act (e.g. stolen vehicle, drunk driver, etc) 1
Wet weather conditions 1
Making a left turn when unsafe 1
Disobeying a traffic sign 1
Overtaking improperly 1








A78 Inverkip Road, Greenock

Failing to maintain a safe distance 9
Making a right turn manoeuvre 4
Dazzled 2
Wet weather conditions 2
Pedestrian crossing carelessly 2
Losing control – other manoeuvre 1
Swerving to avoid a hazard in the roadway 1
Changing lane without ascertaining road is clear 1
Disobeying a traffic sign 1
Criminal act (e.g. stolen vehicle, drunk driver, etc) 1



A761 Kilmacolm Road, Port Glasgow

Failing to maintain a safe distance 4
Pedestrian crossing carelessly 3
Criminal act (e.g. stolen vehicle, drunk driver, etc) 2
Icy / Snowy conditions 1
Losing control on a left hand bend 1
Making a right turn maneouvre 1
Insecure / defective trailer 1
Making a left turn when unsafe 1
Cause unknown 1



The following causations are considered by Strathclyde Police to be partly or wholly related to speed:

- Failing to maintain a safe distance
- Overtaking improperly
- Losing control on a right hand bend
- Losing control on a left hand bend
- Losing control – other manoeuvre
- Excessive speed (speed limit)
- Excessive speed (prevailing conditions)


Regards

Andrew

_________________
It's a scam........or possibly a scamola


Homer Simpson

Thanks for getting this stuff, Andy. Can you please email me copies of the correspondence in case I can get the press interested? I'll check with you before any decisions are made.



I wonder if they know how completely barking that is?

I wonder how they would define 'speed' in this context?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Anything other than stationary I would guess!

Did you get the information I emailed to you Paul?
Results were pretty much the same - excess speed (over the posted limit) accounted for 3% along the Kendal to Windermere stretch through Ings!

These figures for Strathclyde seem to have a common cause near the top....

No wonder it is highest on their list... but could it be addressed by speed cameras?
I dont think so!!
A591 Stats by percentage of causes:

Top 30 causations in Injury Collisions
Dvr. Failed to judge other persons path or speed 10.7%
Dvr. Loss of control 10.1%
Dvr. Failed too look properly 8.9%
Travelling to fast for conditions 5.9%
Careless reckless or in a hurry 5.9%
Dvr. Poor turn or manouvre 5.3%
Slippery road (due to weather) 4.1%
Dvr. Sudden braking 3.6%
Exceeding speed limit 3.0%
Dvr. Passing to close to cyclist,horse,rider or pedestrian 3.0%
Dazzling sun 3.0%
Disobeyed double white lines 2.4%
Impaired by alcohol 2.4%
learner or inexperienced driver/rider 2.4%
Road layout (eg bend, hill,narrow carriageway) 1.8%
Animal or object in carriageway 1.8%
Disobeyed 'Give way' or 'Stop' sign or marking 1.8%
Dvr. Junction restart (Moving off at junction) 1.8%
Aggressive driving 1.8%
driving to slow for conditions or slow vehicle (e.g. tractor) 1.8%
Ped.Failed to look properly 1.8%

_________________
Time to take responsibility for our actions.. and don't be afraid of speaking out!

Translation: The road accident report has been changed in 2005 to now allow us to tick "speeding" as well as the real cause of the accident because our current list makes us look like a bunch of complete idiots.

on a slightly related point, did anyone see 5th gear on Monday? Basically they set up an accident involving a car with buggered suspension tailgating in the wet. Interesting in itself until they decided to blame the accident not on any of these factors but on the tyres - they had 2mm of tread rather than the 3 they're trying to convince us we shouldn't go below. No mention either that you should be watching the road ahead and not just reacting to the car in front.

Hi Paul,

I have sent the correspondance and data to your email; subject heading Fwd: Enquiry about accident statistics in Inverclyde so you know what it's in regard to.


Regards

Andrew

_________________
It's a scam........or possibly a scamola


Homer Simpson

Joshner wrote:




so true

Regards

Andrew

_________________
It's a scam........or possibly a scamola


Homer Simpson

I actually liked it.

I thought the point of the test was to show how tyres are extremely important. Nowhere I saw speed mentioned in it which is good.

Most drivers fail to check their tyre pressure weekly, let alone tread depth.
On my car, any less than 3mm in the wet is fairly dangerous, even at "legal" town speeds. It costs in the region of 600 pounds to replace all four of my tyres, but I still do it. Most people would probably wait until they are barely legal and then maybe replace only the ones that fail the MOT.

Yeah. It annoyed me too. I thought it was massively contrived and misleading. Why couldn't they get one car, and evaluate the braking distances on various different tread depths? Perhaps they tried that and it didn't tell the story they wanted to push?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Simply because it wouldn't have had the same impact.

If someone needs to be told that under 3mm tread depth their wet braking distance is dangerous, they need some sort of shocking TV sequence to notice it. Numbers don't have any effect.

The problem is that most people have failed to notice how tyres sizes have changed in the last 10/15 years.

It is now very easy to buy a bottom of the range Vauxhall Corsa with wide section and low profile summer only tyres, where 2mm tread depth is the bare minimum.

I am all in favour of introducing a 3mm tread depth limit.

see, you've been sucked in by it as well. His braking distance wasn't dangerous. Had he not been tailgating there wouldn't have been a collision despite his "dangerously worn" tyres.
If we want to travel down this ridiculous road then obviously we're going to have to ban all trucks/buses/caravans from the road as there's no way, even with brand new tyres, that they're going to be able to stop as quick as a car.
Do we then ban anything that can't stop as fast as the fastest stopping car on the market?
We'd also have to go and test every tyre to hit the market as there can be several metres difference between different tyres on the same car but even that's not good enough because the tyres that stop you 5m quick in the dry might stop you 5m slower in the wet and vice versa. Don't even mention snow...

I haven't been sucked in by anything mate.
Fact is, less than 3mm of tread is very dangerous in the wet, and we should make sure people do understand that.

Heck, how many of you checked the tyre pressure in the last 2 days when the temperatures rose from 20C to above 30C? That alone makes the tyres a few PSIs more inflated than they should, but unfortunately we are lucky some people check their lights work at night...

I don’t agree with this statement. I have a Vauxhall Corsa with wide section, low profile tyres (from new), and it has extremely good road holding in both dry and wet conditions, even with the minimum of 2mm tread.

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Useless laws weaken necessary laws.

I'm sure even the tyre companies recommend 2mm as the minimum. As for *very* dangerous? Perhaps if you're driving in a monsoon but you don't get too many monsoons in the UK.

What's your evidence?

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

[Novice mode]Isn't tread a compromise between maximum friction of slicks in the dry, and water dispering qualities of the tread in the wet? [/Novice mode]

It would seem that drivers dont get educated how tyres work any more!!

The number of variables is enormous, and we rely on the driver to ensure that some are reduced to a minimum - such as tyre pressure, and amount of wear.
Many plainly fail in this - as pointed out by (goes and copy's and pastes!) fnegroni, and for them, checking down to the last millimetre of safe margin might be too much to expect. If they only rely on a visual inspection, then I would ask for a greater depth.

If a proper inspection for depth and flatspots etc. is carried out, then a lower (present) depth is more than adequate.

I have just replaced three tryes on the grounds that it's summer, and dry, and I am expecting a high mileage, when dry conditions could lead to more wear, and could change from dry to wet in a thunderstorm at the drop of a hat, so it was not worth trying to squeeze out the last few hundred miles from the two tyres which were close.
It was also cheaper to use a local tyre garage (BUDGET franchise), than Kwik-Fit, National or ATS etc. when replacing more than one tyre.
I had the opportunity to compare prices in Kendal, and around Preston/Chorley/Southport, and Budget in Kendal were the cheapest - tyre for tyre!
Price of changing a tyre should be secondary to safety - and many don't seem to know what is safe.

_________________
Time to take responsibility for our actions.. and don't be afraid of speaking out!

Good question.

_________________
CSCP Latin for beginners...
Ticketo ergo sum : I scam therefore I am!

Taking several cars on track days with varying tread depths, plus testing emergency braking at ProDrive's testing grounds.

Proof enough?

Not for me, no. I could offer similar but (more or less) opposite anecdotal evidence.

I also have some considerable difficulty in understanding any mechanism.

Obviously if the tread is insufficient to clear water then an aquaplane condition may start. But we're not talking about aquaplaning are we? I don't understand how it might be possible for a tyre to 'half aquaplane', which may be the claim that's being made. My experience of aquaplaning (very rare on the road, except perhaps for very transient events) suggests that it's all or nothing.

Test tracks might provide unrealistic surface water conditions, where aquaplaning conditions are easy to create.

What we need are independent test results for experiments with controlled and realistic conditions. I expect there are some, but I'm not aware of any.

For now, I'm skeptical about the 'sub 3mm is dangerous' claim.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

no. For starters, if you're relying on emergency braking then you've already failed. Secondly, emergency braking on your "dodgy" tyres in a car in the wet most probably will still stop you faster than a semi (arctic, whatever you want to call them). I ask again, should we ban semis from the road as they're clearly dangerous?
How does, say, a porsche with 2mm of tread on top quality rubber compare to "a reasonably priced car" with brand new super-hard-ultra-long-life-bugger-all-grip tyres?