Speeding causes less than 9% of two vehicle road crashes

SV

Nissan doctor wrote: »

Apologies, I though you ment that the OP was the troll:o

God no, the OP is 100% right

puzzle factory

Nissan doctor wrote: »

Might I suggest some physics lessons?

http://mythbustersresults.com/mythssion-control for who?:)

SV

puzzle factory wrote: »

http://mythbustersresults.com/mythssion-control for who?:)

Impact speed is still 180km/h.

Scotty #

IrishSpeedTraps wrote: »

Why are you stating the obvious? What is your solution? A nationwide blanket limit of 20kmh?

BTW, this thread is about the cause of crashes, not the outcome.

Your original question was why was speeding always the focus.

The answer is: because speed is always a factor. Not "Stop Signs" as you suggest in your OP.

...and yes, it is stating the obvious!

IrishSpeedTraps wrote: »

Why then all the focus on speeding and speed cameras? Wouldn't we save more lives by teaching people to obey stop/yield signs?

I.S.T.

Scotty # wrote: »

Your original question was why was speeding always the focus.

The answer is: because speed is always a factor. Not "Stop Signs" as you suggest in your OP.

...and yes, it is stating the obvious!

It is not always a factor in the cause of the crash, only in 9% of them.

SV

Scotty # wrote: »

Your original question was why was speeding always the focus.

The answer is: because speed is always a factor. Not "Stop Signs" as you suggest in your OP.

...and yes, it is stating the obvious!

but if we forgot all the speeding campaigns and focused on getting people to obey stop signs and moving to the wrong side of the road then we can work with getting rid of 55% of RTAs.

Rather than 9%, nah?

IrishSpeedTraps wrote: »

It is not always a factor in the cause of the crash, only in 9% of them.

He's talking about even moving at all counting as speed. Nice little hole the 'speed kills' campaigners have found.

Nissan doctor

puzzle factory wrote: »

http://mythbustersresults.com/mythssion-control for who?:)

From that link:

"Although the total force was doubled by having two cars"

The theory of that article only applies if both cars were doing precisely 90kmh and were both of precisely the same mass etc. If one car is doing 100kmh and the other was doing 20kmh, newtons third law says that the people in the car that was doing 20kmh would have the vast majority of the force transferred to them, meaning they would come off worse.

MagicSean

IrishSpeedTraps wrote: »

It is not always a factor in the cause of the crash, only in 9% of them.

It's an inaccurate figure. I've mentioned before that these stats are based on Garda reports and Gardaí very rarely note speed as a factor if it is not the primary factor.

Nissan doctor

Scotty # wrote: »

Your original question was why was speeding always the focus.

The answer is: because speed is always a factor. Not "Stop Signs" as you suggest in your OP.

...and yes, it is stating the obvious!

So if thats the view, the only solution is do away with cars altogether, dig up all the roads etc etc and make everyone walk.

Oh no wait....walking pace is a speed too, so we might bump into each other, causing bruising.

We've solved it....star trek style beaming technology is the solution to road deaths!:rolleyes:

SV

Seanbeag1 wrote: »

It's an inaccurate figure. I've mentioned before that these stats are based on Garda reports and Gardaí very rarely note speed as a factor if it is not the primary factor.

So it's grand to use statistics to justify higher insurance premiums for younger drivers and such but when it comes to this they don't count, right? :rolleyes:

I.S.T.

Seanbeag1 wrote: »

It's an inaccurate figure. I've mentioned before that these stats are based on Garda reports and Gardaí very rarely note speed as a factor if it is not the primary factor.

If it's inaccurate, why is it used in an official Govenment document? What else in that report is inaccurate?

Atomic Pineapple

Scotty # wrote: »

Your original question was why was speeding always the focus.

The answer is: because speed is always a factor. Not "Stop Signs" as you suggest in your OP.

...and yes, it is stating the obvious!

Wait, speed or speeding? Obviously speed is a factor in all crashes, without it everyone would be static!

The problem is what is speeding? There are so many factors to take into play when it comes to answering that question, road condition, weather condition, tyre type and condition, traffic conditions, braking ability of the car, and so on that using rigid limits like posted speed limits and a single shot in time from a speed camera to police it is taking the easy way out.

The majority of Irish drivers lack the ability to judge these things for themselves and instead focus on the posted limit and fear the crack down on speed, so instead of increasing driver ability (costs money) we are dumbing it down and using a fear campaign against "speeding" (makes money) in it's place.

Scotty #

IrishSpeedTraps wrote: »

It is not always a factor in the cause of the crash, only in 9% of them.

...but a factor none the less.

I.S.T.

Scotty # wrote: »

...but a factor none the less.

Are you a troll or what?

Scotty #

Nissan doctor wrote: »

So if thats the view, the only solution is do away with cars altogether, dig up all the roads etc etc and make everyone walk.

I didn't create physics. It's not my fault that the faster you hit something the more force is applied.

Fighting Irish

Stupidity/Lack Of Concentration/People Not Knowing The Rules Of The Road

causes accidents



And please, to the people who get angry and flash at you when you overtake them doing 110 on a 100, you are not the law, get a life and go fook yourself!

MagicSean

SV wrote: »

So it's grand to use statistics to justify higher insurance premiums for younger drivers and such but when it comes to this they don't count, right? :rolleyes:

Who said that?

IrishSpeedTraps wrote: »

If it's inaccurate, why is it used in an official Govenment document? What else in that report is inaccurate?

You didnt link a report. You linked a jpg with a very narrow context. It would appear to show the primary causes of Two vehicle collisions where specified. And from the looks of the figures it only covers one months worth of fatal collicions.

The bits in bold are the important parts.

conzy

Its a disgrace that some awful roads have a speed limit of 100km/hr and the motorway has a limit of 120km/hr?

The limit on the motorway should be 140/150km/hr and the limit on a LOT of poor roads around the country should be reduced from 100km/hr to 80km/hr

Atomic Pineapple

conzymaher wrote: »

Its a disgrace that some awful roads have a speed limit of 100km/hr and the motorway has a limit of 120km/hr?

The limit on the motorway should be 140/150km/hr and the limit on a LOT of poor roads around the country should be reduced from 100km/hr to 80km/hr

That wont solve anything.

What we need in my opinion:

• A concerted effort to educate and continually re-educate the driving public and not just the basics, proper education on how to observe and adjust to all conditions.
• A new way of providing a suggested speed per road based on normal conditions but not a strict set limit, this should be a guide whereby people can use it to judge an appropriate speed at which to drive on that road having observed and adjusted to the conditions.
• A way of monitoring traffic over a distance and checking for people who are not capably driving on the road, including an inappropriate speed, both low and high.

BlackBlade

speed doesnt kill lack of skill and bothering your arse to does tho!

gards were told to enforce the 30kph limit in town because pedestrians and cyclist have the highest amount of fatalities in the city but are harder to police so they go for the car driver instead!

I.S.T.

Seanbeag1 wrote: »

You didnt link a report.

I mentioned the name of the report, Road Collision Facts 2009, go ahead and read it, you won't find anything that contradicts what is in that table.

Seanbeag1 wrote: »

You linked a jpg with a very narrow context. It would appear to show the primary causes of Two vehicle collisions where specified. And from the looks of the figures it only covers one months worth of fatal collicions.

Nope, it's figures for the entire year.

Seanbeag1 wrote: »

The bits in bold are the important parts.

In your opinion.

Iwannahurl

Tragedy wrote: »

I've studied thousands of pages of rsa/UK government reports on road accidents and death statistics. All of them broadly agree that statistically, exceeding the posted speed limit is only a contributor to a minority of cases.

Don't lie, thank you.

References and links to some key reports please (but not to the Daily Mail or Telegraph, thank you).

Iwannahurl

draffodx wrote: »

Wait, speed or speeding? Obviously speed is a factor in all crashes, without it everyone would be static!

The problem is what is speeding? There are so many factors to take into play when it comes to answering that question, road condition, weather condition, tyre type and condition, traffic conditions, braking ability of the car, and so on that using rigid limits like posted speed limits and a single shot in time from a speed camera to police it is taking the easy way out.

The majority of Irish drivers lack the ability to judge these things for themselves and instead focus on the posted limit and fear the crack down on speed, so instead of increasing driver ability (costs money) we are dumbing it down and using a fear campaign against "speeding" (makes money) in it's place.

With reference to the OP, the title of the attached table is "Two vehicle collisions: contributory action, where specified".

The total number of fatalities involved is 32. This is about 10% of the total number of fatalities in 2007.

In your opinion do the 32 fatalities referred to in this single table in a single Irish report for a single year undermine the recurrent finding in road safety research internationally that higher speed increases both the risk and severity of car crashes?

Do you believe that the 32 fatalities as reported undermine the evidence for the effectiveness of speed surveillance?

MagicSean

IrishSpeedTraps wrote: »

I mentioned the name of the report, Road Collision Facts 2009, go ahead and read it, you won't find anything that contradicts what is in that table.


Nope, it's figures for the entire year.



In your opinion.

I did read it. It doesn't support you very much. In fact that small table that deals with a small amount of collisions is the only reference to causes other than environmental ones. I've explained to you why it isn't very accurate yet you've ignored it because it doesn't suit you.

I.S.T.

Seanbeag1 wrote: »

I did read it. It doesn't support you very much. In fact that small table that deals with a small amount of collisions is the only reference to causes other than environmental ones. I've explained to you why it isn't very accurate yet you've ignored it because it doesn't suit you.

It is the only table in the report which sets out the primary cause of collisions. Show me something from the report which contradicts what that table says. I am presenting facts backed up by stats in the report. 9% of two-vehicle collisions are caused by excessive speed, that is a fact from this official Government report which you cannot argue with. What have you got to back up your point of view?

_Kaiser_

Seperate wrote: »

I'd say the main reason why someone 'went to wrong side of road' or 'failed to stop/yield' would be mostly due to speed as well.

Not necessarily..

Piss-poor lane discipline generally has to account for some of that - only last night for example did I witness the car in front cut the corner (turning right) from a standstill at a junction and then continue up the road half in the other/oncoming lane for a good 200m before drifting back into the correct lane.

Then you have the idiots who'll overtake on a bend (which in a lot of cases is stupidly marked as being "safe" to do so with dashed lines) regardless of cars coming at them.

Tea drinker

Well it's not 9% from speeding or breaking the speed limit. As I read "exceeding safe speed" it could be less than speed limit, e.g doing 50 kmh around a bend that takes 30km/h or driving at the speed limit in adverse conditions, or when it's just busy.

So exceeding the speed limit might be the cause of 5% of crashes? or only 1% ?

Tea drinker

Kaiser2000 wrote: »

Then you have the idiots who'll overtake on a bend (which in a lot of cases is stupidly marked as being "safe" to do so with dashed lines) regardless of cars coming at them.

the winner is the formation fliers / aerobatic teams whoc stick together no matter the conditions. D1chkhead one overtakes on bend so d1ckhead 2 MUST overtake too.

Sobanek

Nissan doctor wrote: »

So still nowhere near the main cause as the RSA et all claim.




Rubbish, end of.

German autbahns in many cases have no speed limits and they are among the lowest accident/fatality roads in europe.

There has to be limits of course, but current limits, braking distances etc etc are based on car abilities and information from the 60's.

Driver education is also a huge factor.

Well it depends. I do agree with you - the speed is not an issue, it's irresponsibleness. I don't agree with the information from the 60's though.

A 1993's BMW 318i's braking distance from 60mph to 0mph is 112ft.
A 2004's Volvo S40's braking distance from 60mph to 0mph is 114ft.

So it is something you have to take into consideration.

cyclopath2001

IrishSpeedTraps wrote: »

I was just reading through the RSA Road Collision Report 2009 and notice that "Exceeded safe speed" is responsible for less than 9% of all ....Why then all the focus on speeding and speed cameras?

Because speed is a major contributing factor to the extent and seriousness of outcome of an accident regardless of the primary cause, which may or may not be speed.

Depending on the speed, people may be killed, families may be devastated, impoverished, people might be burnt alive, maimed, paralysed for life or hopefully, just suffer recoverable injuries. That's why controlling speed is important.

Or, to put it another way, would you prefer to be hit by an idiot at 50 kph or 80kph?

Atomic Pineapple

Iwannahurl wrote: »

With reference to the OP, the title of the attached table is "Two vehicle collisions: contributory action, where specified".

The total number of fatalities involved is 32. This is about 10% of the total number of fatalities in 2007.

In your opinion do the 32 fatalities referred to in this single table in a single Irish report for a single year undermine the recurrent finding in road safety research internationally that higher speed increases both the risk and severity of car crashes?

Do you believe that the 32 fatalities as reported undermine the evidence for the effectiveness of speed surveillance?

A question for the OP perhaps, I didn't mention said report in any of my posts or refer to it for any of my comments or opinions. In my opinion presenting facts for or against the effectiveness of speed surveillance is pointless as we currently have no way to effectively gather and present all relevant statistics required from every single crash and hence its relatively easy to spin the statistics for either view depending on how the current limited findings are looked at.

cyclopath2001 wrote: »

Or, to put it another way, would you prefer to be hit by an idiot at 50 kph or 80kph?

I'd prefer if proper measures where taken to decrease the likelihood of me being hit at all, eduction would turn that idiot into a competent driver, a speed camera won't.

cyclopath2001

draffodx wrote: »

eduction would turn that idiot into a competent driver, a speed camera won't.

All drivers consider themselves to be wonderfully competant.

Education is not the problem, discipline is.

A speeding fine and some points teach a valuable lesson.

MagicSean

IrishSpeedTraps wrote: »

It is the only table in the report which sets out the primary cause of collisions. Show me something from the report which contradicts what that table says. I am presenting facts backed up by stats in the report. 9% of two-vehicle collisions are caused by excessive speed, that is a fact from this official Government report which you cannot argue with. What have you got to back up your point of view?

Years of experience and attendence at close to a hundred collisions.

You have used a narrow statistic to try and prove a point about something much wider. Even your thread title is misleading. Your statistic covers a very small percentage of collisions and only covers the primary cause. Even at that I've explained to you why it can be misleading but you won't accept it. You won't argue it you just refuse to acknowledge it.

gyppo

Another fine thread started by a poster who doesnt have a vested interest or doesnt derive income from the sale of speed camera locations.

While I won't disagree with the fact stated regarding the 9% figure, speed, whether excessive for the given conditions, or above the posted levels, has a huge significance where an accident is concerned.

Why not take a look at this study
http://http://www.rte.ie/news/features/roadsafety/publications/MaxillofacialInjuries.pdf

Speeding and maxillofacial injuries: Impact of the
introduction of penalty points for speeding offences

For those who can't be bothered to read it, it was conducted 1 year after the introduction of the penalty points system. This was when there was a widely perceived view that there was a great risk of being caught and penalised for breaking the speed limit.
"The introduction of legislation led to a 61% reduction in the need for emergency maxillofacial operations."

So, its ok to be complacent about speed, as it only accounts for 9% of accidents - Fair enough then so:rolleyes:

Iwannahurl

draffodx wrote: »

A question for the OP perhaps, I didn't mention said report in any of my posts or refer to it for any of my comments or opinions.

In my opinion presenting facts for or against the effectiveness of speed surveillance is pointless as we currently have no way to effectively gather and present all relevant statistics required from every single crash and hence its relatively easy to spin the statistics for either view depending on how the current limited findings are looked at.

Are you posting in the wrong thread then, or just a little off topic?

The thread title is "Speeding causes less than 9% of road crashes" and this claim relies on a single table which refers to a total of 32 fatalities in a single year.

Quote: "I was just reading through the RSA Road Collision Report 2009 and notice that "Exceeded safe speed" is responsible for less than 9% of all crashes." Emphasis added.

Presumably you have some opinion of the OP and the claim made explicit in the thread title and repeated in the quote above, or maybe you wouldn't have thanked it (along with a dozen others so far)?

bluewolf, Bullseye1, Divorce Referendum, dr.fuzzenstein, draffodx, Fighting Irish, Jimmy Bottlehead, koth, Limerick man, Nissan doctor, opinion guy, Vertakill, Voodoomelon

Do you believe that the OPs attached table can be used to draw generalisable conclusions about speed and speed surveillance or do you not?

And btw are you possibly implying that it is "pointless" to rely on established evidence regarding the effects of speed cameras?

Iwannahurl

gyppo wrote: »

Why not take a look at this study
http://http://www.rte.ie/news/features/roadsafety/publications/MaxillofacialInjuries.pdf

Speeding and maxillofacial injuries: Impact of the
introduction of penalty points for speeding offences

For those who can't be bothered to read it, it was conducted 1 year after the introduction of the penalty points system. This was when there was a widely perceived view that there was a great risk of being caught and penalised for breaking the speed limit.

"The introduction of legislation led to a 61% reduction in the need for emergency maxillofacial operations."

I wasn't aware of that study. I haven't looked at it yet either, but presumably it gives a plausible explanation as to why there might have been such a significant drop in injuries of that type within 12 months of penalty points being introduced.

Of course there are penalty points for a range of road traffic offences, not just speeding (though speeding is perhaps the single biggest reason for receiving penalty points).

IIRC there was also a marked drop in fatalities the year random breath testing was introduced.

Such beneficial effects can wear off a bit, however, if enforcement is not kept up. More is needed, along with better driver education too.

Atomic Pineapple

cyclopath2001 wrote: »

All drivers consider themselves to be wonderfully competant.

Education is not the problem, discipline is.

A speeding fine and some points teach a valuable lesson.

Education and re-education would deal with discipline in most drivers.

Lessons learnt from points are short lived at best. And all it does is slow people down for a while, not improve their driving.

Iwannahurl wrote: »

Are you posting in the wrong thread then, or just a little off topic?

The thread title is "Speeding causes less than 9% of road crashes" and this claim relies on a single table which refers to a total of 32 fatalities in a single year.

Quote: "I was just reading through the RSA Road Collision Report 2009 and notice that "Exceeded safe speed" is responsible for less than 9% of all crashes." Emphasis added.

Presumably you have some opinion of the OP and the claim made explicit in the thread title and repeated in the quote above, or maybe you wouldn't have thanked it (along with a dozen others so far)?

bluewolf, Bullseye1, Divorce Referendum, dr.fuzzenstein, draffodx, Fighting Irish, Jimmy Bottlehead, koth, Limerick man, Nissan doctor, opinion guy, Vertakill, Voodoomelon

Do you believe that the OPs attached table can be used to draw generalisable conclusions about speed and speed surveillance or do you not?

And btw are you possibly implying that it is "pointless" to rely on established evidence regarding the effects of speed cameras?

There are many reasons I would thank a post, thanking it does not automatically mean I agree with 100% or with any links presented in the post. I didnt quote the OP in any of my posts and instead I was clearly commenting on further comments on the thread which had expanded the topic somewhat.

I believe it is pointless to present it for a topic of conversation on an internet forum as it can easily be "skewed" to suit one or the other point of view.

Scotty #

draffodx wrote: »

Education and re-education would deal with discipline in most drivers.

I doubt it. I know most, if not all drivers, know it is illegal to use a mobile while driving and yet I see hundreds doing it everyday. Driving over the speed limit, the use of lanes, (as is being advertised on TV at the moment). People do actually know the rules of the road for the most part. Education does not mean compliance - unfortunately. Knor does penalisation - but it helps.




(Personally I think motoring fines is this country are ridiculously low but I dare'nt bring that up here!:p)

Iwannahurl

Less than 9% of opinions are caused by solid evidence.

Tea drinker

Both education and discipline are issues. But dealing with ignorance thru education is the most fruitful approach imho.
Until we are all doing a mandatory full 1 day training course every 2 years we are not dealing with the issues. You can have an "Uncle Gaybo" or rambo cutout on every second corner and a speed camera on the rest, still won't fix ignorance of other road users. Until all people are trained, cyclists, pedestrian truck drivers, and trained from the point of view of each other we won't get it. As we are talking about car accidents here sure more education is good, much better than speed camera's on straight stretches of road. I mean the lie of the camera there to help while it's just printing money is galling. We were lied to that they would only be put in blackspots and it seems it everywhere except.

Road safety is simply not taken seriously, and until we get over that, kiss someone you know goodye. Better that than making a fuss or noise - what would people think?

Welease

IrishSpeedTraps wrote: »

Hi All,

I was just reading through the RSA Road Collision Report 2009 and notice that "Exceeded safe speed" is responsible for less than 9% of all crashes. "Went to wrong side of the road" is the highest cause at 32% followed by "Drove through stop/yield sign" at 20%. Why then all the focus on speeding and speed cameras? Wouldn't we save more lives by teaching people to obey stop/yield signs? Any comments?

(See attachment for stats from the report)

I didn't bother to read the previous posts...

But ...did you look at the stats you posted?

2 people died by Driving through Stop/Yield signs..
8 people died by exceeding safe speed...

How would we save more lives by diverting focus to issues which have caused 4x times less fatal crashes?

cyclopath2001

draffodx wrote: »

Education and re-education would deal with discipline in most drivers. Lessons learnt from points are short lived at best. And all it does is slow people down for a while, not improve their driving.

Unless the education includes community service attendandance at RTAs or witnessing painful A&E procedures as bits of cars are removed from peoples bodies, I think additional penalty points, increased insurance premia and eventual disqualification will slow people down.

draffodx wrote: »

I believe it is pointless to present it for a topic of conversation on an internet forum as it can easily be "skewed" to suit one or the other point of view.

The topic itself, as presented, misrepresents the reasons why we need to control road speeds.

slimjimmc

Nissan doctor wrote: »

But if two cars are perfectly safely doing 90kmh on a straight national road and one falls asleep or whatever and veers to the wrong side, then the impact will be 180kmh, very likely resulting in deaths. But to say speed was a factor in that accident is silly as neither were speeding.

So to prevent a death in that accident, the speed limit would have to be 20-25kmh so that any possible head on impact would be limited to 40-50kmh? That's just ridiculous IMO.

If we are to get into obscure arguments...then why not say all the road deaths are the governments fault? The government have not provided proper driver education or testing standards and are now blaming and penalising motorists for the resulting accidents.

Building site foremen/company owners etc get fined or worse if proper training has not been provided to a worker who injures/kills himself so whats the difference?

It is incorrect to add the speeds of both vehicles in a head-on collision and say the impact is equal to the sum of the speeds. As far as each car is concerned a head-on collision at 20kmh with another car is equivalent to a 20kmh head-on collision with a tree. Differences such as mass, velocity, structural rigidity and impact vector will have a minor effect though.

It has no basis in physics and has been disproved.
http://warp.povusers.org/grrr/collisionmath.html
Mythbusters episode

Absurdum

Guy:Incognito wrote: »

How can they generate revenue from people obeying the rules?

that's exactly what the speed camera operators/overlords should be aiming for - zero revenue

I'd bet my shirt that if they weren't pulling in the €'s in one location, they'd be moved somewhere else.

dharn

its not speeding that will kill you, it is stopping suddenly !!

Welease

Absurdum wrote: »

I'd bet my shirt that if they weren't pulling in the €'s in one location, they'd be moved somewhere else.

But doesn't that mean that they are targetting the areas where more people are breaking the law?

challengemaster

Welease wrote: »

But doesn't that mean that they are targetting the areas where more people are breaking the law?

Breaking the law and doing a safe speed are two massively unrelated things.

There's a dual carraigeway in Galway that has a 50km/h limit on it

Here

But this road has an 80km/h limit on it

Here

Which do you think is more likely to cause a crash - doing 54km/h on the dual carraigeway above, or doing 80km/h on the back road?

Welease

challengemaster wrote: »

Breaking the law and doing a safe speed are two massively unrelated things.

There's a dual carraigeway in Galway that has a 50km/h limit on it

Here

But this road has an 80km/h limit on it

Here

Which do you think is more likely to cause a crash - doing 54km/h on the dual carraigeway above, or doing 80km/h on the back road?

I am fully aware of the rediculous speed limits in Ireland.. Ouside my house is a 1 lane road with an 80Km speed limit (similar to the one you posted).. whereas the main road is 60Km..
In many many cases they make no sense.. But, until changed they are the legal limit for that road.

But.. the point was in answer to the previous post, so must be taken in that context...

The revenue is being generated because thats where the laws are being broken.. The poster stated it would be moved if revenue dropped.. It likely would be, as that would be an indication that less people were breaking the law..

I don't necessarily agree or disagree with speed cameras, I was pointing out the logic to the previous poster.

SV

dharn wrote: »

its not speeding that will kill you, it is stopping suddenly !!

but do you think my suggestion for marshmallow crash barriers was taken seriously? Nope.

Iwannahurl

slimjimmc wrote: »

It is incorrect to add the speeds of both vehicles in a head-on collision and say the impact is equal to the sum of the speeds. As far as each car is concerned a head-on collision at 20kmh with another car is equivalent to a 20kmh head-on collision with a tree. Differences such as mass, velocity, structural rigidity and impact vector will have a minor effect though.

It has no basis in physics and has been disproved.
http://warp.povusers.org/grrr/collisionmath.html
Mythbusters episode

I wonder whether this has ever been discussed in a Boards thread? I'll bet it would make for quite a divisive argument!

In an idealised situation where both colliding bodies just happen to be identical, then this is true in a pure Physics sense.

However, real life is never like that. If I was to be involved in a head-on collision between, say, a Hummer and a Smart car, both travelling at the same speed, I know which vehicle I'd prefer to be in. The Hummer has much greater mass (four times as much?), and will be slowed to some degree but not stopped when it hits the Smart car. The Smart car, on the other hand, will abruptly decelerate to zero and then be rapidly accelerated in the opposite direction up to the speed the Hummer is still travelling at. That would be like hitting the tree at a much higher speed. If I was travelling in the Smart car I'd prefer to hit a tree rather than a Hummer at the same speed.