Road safety advert inaccuracies - Hawesy1982
Kind of linked to the thread on the "Now you see him, now you see him" road safety ad that has been running recently, i'd just like to point out another road safety ad inaccuracy that really really annoys me.

Whilst generally i think the vast majority of road safety ad's are brilliantly done and hard hitting (especially the seatbelt ones btw), there is one concerning the importance of sticking to the 30 limit that has a glaring error in it.

"If the car had been travelling at 30mph, it would have stopped...here." Just before the car ploughs into a small child.

HOWEVER

All through the length of the ad, the car has its brakes locked!

When skidding, the car has very little stopping power, and so im sure if the car WAS travelling at 30(or less) and had braked in the manner shown, it would also have hit the child!

Surely the producers shouldn't have used a car with locked wheels to demonstrate this, even if it does look more exciting on tv. If that is how the majority of accidents occur, the ad should have been explaining that for cars without ABS keeping the brake pedal floored whilst skidding is NOT the most efficient way of stopping!
Road safety advert inaccuracies - Altea Ego
Sorry plain wrong. In the dry with locked brakes/wheels a car has considerable stopping power. What you dont have is control.

The stopping distance at 40 mph with locked brakes is considerably longer than one at 30 with locked brakes.
Road safety advert inaccuracies - martint123
Agree with the first poster - locked brakes equals very little braking effect. Maximum braking is just at the point when the tyre starts slipping. Can't remember where it was, but ISTR that locked brakes can add 50% to your stopping distance (on a dry road) on wet or icy roads considerably more.

p.s. why are the rear wheels not locked as well??
Road safety advert inaccuracies - Altea Ego
Sorry - still wrong. Locked brakes in the dry have very similar stopping distances to ABS. The pont about maximum stopping just before point of slipping applies in the WET OR ICE only. ABS DOES NOT STOP YOU FASTER IN THE DRY. It only gives you control to steer.
Road safety advert inaccuracies - Doc
Sorry, don't agree.


When lockup occurs, the driver loses all operational and steering control because of a loss of friction between the vehicle's tyres and the road surface.

When wheels lock up, most of the friction is lost, causing the vehicle to skid out of control.
The friction while sliding is greatly decreased and it takes a much greater distance to stop. Therefore, brake lockup is not a safe or effective braking procedure.

Road safety advert inaccuracies - GJD
That one\'s been around for a while hasn\'t it. As well as the locked wheels problem (agree with all you say), the car is driving down a busy looking high street with IIRC parked cars, pedestrians a zebra crossing etc. such that 30mph is probably too fast for the conditions.

This is not mentioned at all. The message is that the driver\'s mistake was exceeding the posted limit, thereby reenforcing the misconception that the limit is a safety target, not a legal *maximum*.

Not impressed.
Road safety advert inaccuracies - neil
Some good stuff here!

Yes, locked wheels/dry road is potentially the fastest stop - although completely out of directional control.

Yes, locking OFF the back wheels of the car hardly gives a fair demonstration - it just looks 'rigged' to people who know cars.

The campaign about what speed its preferable to hit pedestrians rather misses the point - unlike the brainwashed masses, who will presumably continue to feel smug at 28mph, texting and eating their sandwiches, and secure in the knowledge that the poor sid they hit is less likely to die. Oblivious however to the fact that the ped would be less uncomfortable still, had they chosen to stay alert to the possibility of having to move the wheel sufficient - while off the brakes - to steer the whole two feet it would have taken to miss them altogether...!

Great stuff. Speed kills, ya know! (Possibly not as much as complacency, but there wasn't room for that on the back of the buses! Plus, it's not as easy to tax!)
Road safety advert inaccuracies - jeds
Dynamic friction is the friction between two moving parts - i.e. sliding friction. Static friction is the friction between two stationary parts, i.e. sticking friction.

The coefficient of dynamic friction between rubber and dry tarmac is about 0.91. The coefficient of static friction is about 1.00

Therefore, a skidding car will have a longer stopping distance than a non skidding car. The difference is quite small though.
Road safety advert inaccuracies - Sooty Tailpipes
If you are braking on the threshhold, and then the front wheels lock, you can feel the retardation becomes less, and the nose will rise slightly as the wheels lock. Funnt thing is, BMW ran driving courses in the '90s which taught the opposite.

I hate that ad, it's so obvious the car has defective brakes, I think the rear ones had been greased up
Road safety advert inaccuracies - Altea Ego
The similarities were proved to me on a defensive driving course. We were given two identical cars - Volvo s40's. One with its abs intact and one disabled. Told to drive at an indicated speed, brake hard at a marker, and the distance to stop measured. The difference (the none abs one was about a yard shorter) could be easily explained by reaction times etc.

Then a cone was placed in the braking zone and you had to avoid the cone with both cars while braking hard. Of course with the none ABS car the cone was hit because you either had to come off the brakes or hit as no direction control was possible.

The point they were proving was that ABS made your stopping distance no shorter, and you could not think ABS would allow you to leave smaller gaps between you and the car in front. They were also teaching how to use ABS ie steer and brake at the same time.

This all goes out the window of course in the wet, when ABS will allow shorter braking distances and directional control against a non ABS car.

It all goes to prove of course that ABS is a win win situation in all circumstances, even in thick snow or gravel where the wedge effect will shorten stopping distances in a non ABS car, but of course you still have no steering. It is high time ABS was made mandatory on new cars, and its use covered in the driving test.
Road safety advert inaccuracies - Obsolete
I agree. I thought the advert was saying that as long as you drive at the limit you are a safe driver. If the child was close enough to the road to run in front of a car, then 30 mph would have been a reckless a speed. It struck me as a dangerous advert.
Road safety advert inaccuracies - Sooty Tailpipes
Yes, reminds me of a sign at a railway station which states, "To ensure total safety, do not cross this line"

Which of course is nonsense, there is no such thing as total safety.
Road safety advert inaccuracies - NorthernKev {P}
Would it be safer for the car to have been driving at 40 and braked when it did, or the driver to be driving at 30 and not seen the kid and not braked?
Technically safe as he was \'doing the speed limit\'...

Hmm!!

Kev
Road safety advert inaccuracies - Dan J
The point the advert has to make is valid, but the way the advert has been done is a joke.

A car whose brakes responded in that manner would not have passed its MOT and shouldn't be on the road anyway.

For anyone who'd like to argue - get someone you know to film you anchoring on the brakes from 30mph on a straight piece of road...

Additionally - laws of physics: You cannot brake harder than the coefficient of friction between the tyres and the road. Subsequently, you could, in theory, stop as quickly without skidding but you won't stop any faster if you are. Anyone who has felt the effect of ABS against their foot on harsh braking knows the system is effectively backing off. All this does is allows the wheel(s) in question (in all cases at the front of the vehicle) to continue braking with reduced force but to allow movement. As RF discovered, this does marginally increase your braking distance (remember, you can't apply more force hence brake harder than the coeff of friction between tyres and road) but what it does do is give traction back to the front wheel(s) and allow steering. Hence therefore when little Jonny walks out in front of you and you steer and stamp on the brakes - natural reaction even if "incorrect", the ABS car may take extra inches to stop, but as the car was able to follow the path you were steering in, Jonny is stood in the road crying and you are pondering your pants collection. As opposed to something much worse.

ABS - particularly in modern applications, can turn a driver mistake on a wet and windy country road into something unpleasant instead of horrific.

I always used to take a cocky view that anyone who needed ABS or was incapable of controlling a car without it wasn't a very good driver. Mind changed now though - I've seen the test videos engineering use and they're frightening. I hope it never happens to any of us but the day someone walks out in front of your car, see how high on your natural reaction list cadence braking is....
Road safety advert inaccuracies - Garethj
A small point, but it's unlikely there is anything wrong with the rear brakes on the car in the film. For about the last 20 years cars have had a pressure limiter in the rear brake hydraulic line which limits the braking force and should stop rear wheel lock up. If the front wheels lock you get no steering, but if the rear wheels lock you can be spun around before you know it. It was a crude form of ABS, relying on the fact that the rear brakes don't do much anyway on most front engined cars due to weight transfer.

Gareth
Road safety advert inaccuracies - volvoman
IMO this advert is valid but has clearly been designed to convey a relatively simple message to the average motorist as vividly as possible. In essence an extra 10mph requires quite a lot more stopping distance than you might imagine and thereby increases the chances of a fatality in an accident. Obviously many of those who frequent this forum are technical experts of one sort or another and can identify possible inconsistencies in such an advert. Whilst these are certainly worth pointing out, I'm not sure they obviate the need for such a message which is clearly targeted at the masses. In terms of the value of ABS, I have read what's here and it's clear that there's some degree of difference even amongst those who seem to know quite a lot about cars and their safety systems. For me ABS had always been an acronym synonymous with safety but that's about it. ABS = safer braking and shorter stopping distances. Obviously I was wrong. I'm starting to wonder whether all these safety gizmos can engender a false sense of security amongst some of those who don't really understand what they do and how they work. Perhaps we'd all benefit by being given more information on these systems, what they're capable of/designed for and what they're not. But, when all said and done, you can have any amount of safety systems on board and still be a bad, and dangerous driver capable of killing yourself and others around you.

As for the ad., there's no easy way to create something which will convey a clear unequivocal message universally. I just think that anything which makes drivers and pedestrians more aware of the dangers around them is valid, even if a degree of artistic licence has been used to achieve that effect.
Road safety advert inaccuracies - Phoenicks
People talk about braking differences and how 'thats the effect at 30mph' but every car has different braking levels with some being massively better than others - witness porshce/ferrari carbon brakes. admittedly rare though.

We still use guidlines in the highway code for cars built 30 years ago whereas cars nowadays are vastly improved and so has tyre technology. Perhaps its time to update the 'industry standard for safety'braking distances

on a abs - good or not note, my golf recently had ABS system failure (simply a broken sensor) but for 3 days i had no ABS, but did have full brakes. And it braked a helluva lot better and quicker without ABS....
Road safety advert inaccuracies - volvoman
A limit of whatever kind is a very coarse measure by definition. Cars have imporved by miles since the limits were introduced as have braking, tyre, steering and safety technology. However, we can only have one limit which has to apply to all cars, even older ones. That does mean that if you have a certain type of car you could stop well within the distance required by another car even if you are driving considerably faster. Deciding where to set limits, how to promote safety and how to explain technology appropriately for everyone is very diffcult. What seems simplistic, inaccurate or even patronising to some may be going well over the heads of others and it is these 'others' I think we need to be most conscious of. They are probably the majority of drivers who know little about their cars and have little real understanding of the risks involved in driving. These would include the sort of people who let their kids, dogs etc. travel around unrestrained and haven't got a clue how dangerous it is. They'd include all the people who read maps, answer phones, put their make-up on and even shave whilst driving. If someone could come up with a safety message appropriate for the expert, the ordinary, the inept, the reckless and the blase driver I'm sure we'd all be a lot better off but that really is a big ask.
Road safety advert inaccuracies - Garethj
A few years back Jeremy Clarkson did a comparison test of braking distances on TV. The first test was in a Ford Anglia and it stopped within spitting distance of the distance in the highway code. Brakes were locked, tyres smoking and he was terrified.

The next test was in something modern and sporty, something like a Porsche with ABS, huge disc brakes and sticky tyres. Naturally this stopped much quicker in perfect control and it was as stressful as tuning the radio.

The final test was with a Land Rover Discovery, which was reasonably controlled but stopped within a few feet of the Anglia / highway code distance!
Road safety advert inaccuracies - Cardew
Phoenicks
"on a abs - good or not note, my golf recently had ABS system failure (simply a broken sensor) but for 3 days i had no ABS, but did have full brakes. And it braked a helluva lot better and quicker without ABS...."

Surely in normal use you cannot tell if your car has ABS or not. I have driven cars with ABS for many years and I can count on one hand the number of times ABS has been activated(other than to test it) - it is unmistakeable when it does. That has only occurred during 'panic' stops.

C
Road safety advert inaccuracies - GJD
IMO this advert is valid but has clearly been designed to
convey a relatively simple message to the average motorist as vividly
as possible. In essence an extra 10mph requires quite a
lot more stopping distance than you might imagine and thereby increases
the chances of a fatality in an accident. Obviously many
of those who frequent this forum are technical experts of one
sort or another and can identify possible inconsistencies in such an
advert. Whilst these are certainly worth pointing out, I'm not
sure they obviate the need for such a message which is
clearly targeted at the masses.


Leaving aside all technical discussion about braking and locked wheels, the message this advert conveys to the masses is dangerously wrong. The whole thrust of the ad is that at 35mph you hit the child but at 30mph you miss. The conclusion is that if you drive at the posted limit instead of 5mph above it you are a much safer driver.

There are already far too many drivers who have been convinved that the single most important thing they can do to make themselves safer is to ensure that they never exceed a speed limit. But surely developing* the judgement to continuously adapt your speed to the prevailing conditions, which includes developing hazard perception, is far more important.

I have never seen a road safety film point out that there are times when driving at the posted limit is dangerous.

GJD

* By development, I mean an ongoing process. You (ought to?) get better with more experience, but you never reach the point where you know everything. Or do we really believe it is appropriate to give driving licences to people who aren't even capable of that?
Road safety advert inaccuracies - GrumpyOldGit
"I have never seen a road safety film point out that there are times when driving at the posted limit is dangerous."

Please could you give me any examples of when driving at the posted limit is dangerous?


"Or do we really believe it is appropriate to give driving licences to people who aren't even capable of that?"

It is quite obvious to me that we do. Many drivers show no improvement at all even after years of experience.

This ad is aimed at the general public. It puts over a very simple message. Exceed the speed limit and you stand more chance of injuring or killing someone. It might not be technically exact, but the message seems perfectly clear to me.
Road safety advert inaccuracies - Blue {P}
Please could you give me any examples of when driving at
the posted limit is dangerous?


Try going past a school at kicking out time at the posted 30 mph limit.

If you tried that round my old school it wouldn't take many drives past before you had killed someone.

Blue
Road safety advert inaccuracies - blank
"I have never seen a road safety film point out that
there are times when driving at the posted limit is dangerous."
Please could you give me any examples of when driving at
the posted limit is dangerous?

How many would you like?

1 - When there is a slower or stationary vehicle infront of you
2 - When corners are too tight to navigate safely at the speed limit
3 - When you cannot see far enough ahead of you to stop in the distance you can see

I could go on, but I won't. The message in the film is very clear, but I agree with many of the posters here. The Gov't appears to be putting across a single message that speed is bad. In appropriate speed is certainly unsafe, but firstly, inappropriate speed is about much more than the speed limit and secondly, there are many other problems.
Going back to the ad, the stopping distance consists of reaction time plus braking distance. Somebody tuning the radio, lighting a fag, eating a sandwich etc, but driving at 30 could have a linger stopping distance than someone else driving at 50 and using good observational techniques.
All of the above is not meant to condone breaking speed limits in any way, but I believe that the single "speed kills" message leads the majority to concern themselves only with speed and not the other aspects of safe driving.

Andy
Road safety advert inaccuracies - Bromptonaut
Surely the ad is aimed for impact and at those who are "only doing ten miles over the limit". Deeper analysis is intersting but does not remove the fundamental message that 10mph can be life or death. Mobile users, sandwich scoffers and ciggy lighters need their own ad.

Road safety advert inaccuracies - GJD
Surely the ad is aimed for impact and at those who
are "only doing ten miles over the limit". Deeper analysis is
intersting but does not remove the fundamental message that 10mph can
be life or death.


40mph in a 30 zone can be life or death. But 30mph in a 30 zone can also be life or death if the conditions are such that anything faster than 20 is inappropriate. It is that vital distinction between the speed *limit* and an *appropriate* speed that is missing.

GJD
Road safety advert inaccuracies - Obsolete
My own comments that the ad was potentially dangerous were based on 2 recent experiences where I had to run to get out of the way of a car that was in each case probably just within the limit. In each case I was probably crossing the road in a reasonable and responsible manner.

Anyway, 30 mph in a residential area, with a 30 mph limit, and with parked cars either side, is far too fast and is enough to kill, especially elderly people who aren't too fast on their feet.
Road safety advert inaccuracies - Obsolete
I should add that I see loads of police cars stopping people on motorways for exceeding the speed limit. Motorways are the safest roads and these people are easy targets so I do wonder why they stop them. I very rarely if ever see the police in our area targeting dangerous drivers including speeders. Too busy getting the easy targets to achieve gov. targets perhaps?
Road safety advert inaccuracies - GJD
"I have never seen a road safety film point out that
there are times when driving at the posted limit is dangerous."
Please could you give me any examples of when driving at
the posted limit is dangerous?


Blue Oval has already suggested the classic example of a school at kicking out time. 100 yards either side of the school and 30 is often fine.

To get to my house I drive down a couple of terraced streets with cars parked down either side. The road is effectively single track. I am looking for children, cats, footballs and so on to suddenly appear (as they occasionally do). 30mph would be extremely reckless because I am mainly concentrating on the distance only two or three parked cars ahead.

And the advert in question shows a generally busy town high street. Include a bit more traffic, pedestrians, a zebra crossing, buses pulling in or moving off, cyclists. Anyone who believes that the most effective single thing they can do to increase the chance of getting through that without causing an accident is to concentrate on not exceeding the speed limit should not IMO hold a driving licence. For the state to promote their misconception is criminal.
"Or do we really believe it is appropriate to give driving >> licences to people who aren't even capable of that?"

It is quite obvious to me that we do. Many drivers show no >> improvement at all even after years of experience.


Hardly surprising given that there is so little support or reward for improvment.
This ad is aimed at the general public. It puts over
a very simple message. Exceed the speed limit and you
stand more chance of injuring or killing someone. It might not
be technically exact, but the message seems perfectly clear >> to me.


I never said the message wasn't clear. Its vivid clarity is precisely the problem, because it is a gross oversimplification that promotes the dangerous belief that adhering to the speed limit is the essence of safe driving. Hazard perception and anticipation are orders of magnitude more important.
Road safety advert inaccuracies - Welliesorter
I wonder if the average viewer is examining it as minutely or subjecting it to such detailed analysis.

I just took the message of the ad to be the greater the speed, the longer the stopping distance, which seems sound enough.
Road safety advert inaccuracies - GJD
I wonder if the average viewer is examining it as minutely
or subjecting it to such detailed analysis.


Probably not. Although my objections to the locked brakes and the focus on the speed limit instead of safe speed were immediate and instinctive the first time I saw it. No examining or analysis was necessary.
Road safety advert inaccuracies - Peter D
The greatest braking efficiency is just before the wheel locks that is why modern ABS systems stop a car in a shorter distance than a car with its wheels well lock up. The abs puched the whells through the Lock up point several times a second and takes advanage of the dynamics of frictional braking. And yes ABS does give greater control to the driver. Thus the bumper sticker "ABS. I can stop can you ?" Regards Peter
Road safety advert inaccuracies - GrumpyOldGit
Please could you give me any examples of when driving at
the posted limit is dangerous?


Doh! I took that comment to mean driving above the limit. Didn't think of lower - sorry all!
Road safety advert inaccuracies - Cardew
I lived in Germany in the 60s when Mercedes were the first to fit ABS to production cars as a trial. To selected buyers of the 450SEL 6.9, ABS was fitted free and owners completed questionnaires after using it for a while.

The outcome was that a significant number had damage to the rear of the car when they 'collected' cars whom they had simply outbraked - usually from high speed on the Autobahn.

There was a considerable debate on the wisdom of fitting ABS as these cars were more likely to be involved in accidents than non ABS cars.

In real motoring I suggest that this illustrates that ABS cars stop quicker and the manoeuvrability under braking is a bonus.
Road safety advert inaccuracies - neil
Hmm... I don't think any car or brake manufacturer has ever claimed shorter stopping distance as a benefit of ABS - although you say 'thus', the sign you mention is as relevant as the 'my other hat's a trilby' and 'baby on board' stickers. they help identify the kind of driver, but little else!
Road safety advert inaccuracies - Hawesy1982
Wow, thanks for all the replies so far, makes me proud to have started such an active thread!

Must say i agree totally with many of you, especially GJD and others who have said this advert just jumped out as being slightly contrived to me, but i'm not taking anything at all away from the majority of very good, hard-hitting safety adverts that have been screened in the past few years, and if this one succeeds in making just one bad driver think twice about speeding, it will have done its job in part.

As most people have said, it is often the case in built-up areas that simply INAPPROPRIATE speed kills, not necessarily illegal speed, and i agree that this is one of the next aspects of driving that should be supported by an ad campaign.

Oh and whoever wanted examples of where it is dangerous to go at the posted limit, i was driving through France this January, in heavy snow, and whilst the limit was 130km/h on a french motorway, everyone was going less than 20mph in the slow lane, just to stay on the road. Some young french girl goes past in a renault 5 in the outside lane at about 30, and promptly understeers straight into a lamppost. QED i make that!
Road safety advert inaccuracies - Baskerville
IMO this advert is valid but has clearly been designed to
convey a relatively simple message to the average motorist as vividly
as possible. In essence an extra 10mph requires quite a
lot more stopping distance than you might imagine and thereby increases
the chances of a fatality in an accident.


No I don't think that's the point at all: it's not about avoidance. I reckon the point is that in a situation where you can't avoid hitting a child (i.e. the actual impact is not your fault) it's better to do it at 30mph and falling than at 40mph and falling: survival rates in accidents improve as the speed at time of impact reduces. In that sense, speed kills. Avoidance is an important issue but it's secondary to this campaign.
Road safety advert inaccuracies - Baskerville
Engage brain before sending: note I'm talking about the campaign in general, not just this "would have stopped here" ad.
Road safety advert inaccuracies - NorthernKev {P}
Or swerve out the way of the kid...
Or notice the kid in the middle of the street earlier, it hadn't just 'appeared' there, you will notice it's stationary.
Or the kid not standing still in the way of a 'busy' high street, but that suggests it's not the motorist's fault...

Kev
Road safety advert inaccuracies - Obsolete
At the risk of flogging a horse while it is receiving last rights ...

Avoidance should be the primary goal as an aware and responsible driver should never get into the situation shown in the advert. It's about matching speed to road conditions.

My concern is that there are some people who think that the solution to all road accidents is to slow traffic to less than 20 mph regardless of road conditions etc. Then we will end up with roads that are barely navigable due to absurd limits, road humps that increase pollution and noise and which damage and slow emergency vehicles, ill phased traffic lights that increase pollution, road constrictions that direct cars into cyclists and are used by some as slaloms and other nightmares.
Road safety advert inaccuracies - James_Jameson
Leif - you're quite correct.

I just have to say that the nanny state is taking away people's ability to think for themselves. People are becoming increasingly dependent upon the state to tell what and what not to do, what is safe and what is not. To keep to the motoring theme, not so long ago, in schools, children were taught to stop, look and listen before crossing the road. If the child were sadly run over, the implication was that it was the child's fault, for not heeding what they were taught and not looking out for themself.

Now, in driving (as well as in life in general in the UK), it's becoming difficult to think of a scenario where one is able to think for oneself at all without falling foul of some law.

One example: it seems that many of the more sheep like members of our society have become brainwashed into thinking that overtaking is in some way a sin, by flashing their lights and gesticulating like idiots at the most safe overtaking manoeuvre.
Road safety advert inaccuracies - SR
Maybe the reason the "nanny state" is taking away people's ability to think for themselves is that so many people demonstrate a complete inability to do so.
Road safety advert inaccuracies - GJD
Maybe the reason the "nanny state" is taking away people's ability
to think for themselves is that so many people demonstrate a
complete inability to do so.


Maybe the reason people can't think for themselves any more is that the "nanny state" has taught them that they don't need to.

Cause and effect. Chicken and egg.
Road safety advert inaccuracies - Obsolete
Maybe the reason the "nanny state" is taking away people's ability to think for themselves is that so many people demonstrate a complete inability to do so.

Are you by any chance referring to council road engineers? (A tongue in cheek comment.)

Seriously though, dangerous driving esp. in residential areas is a serious problem. I mentioned earlier 2 recent occasions when I had to run for safety while crossing a road to avoid being hit by an arrogant moron in a car. Lord help the elderly and the infirm.

The problem is that a lot of the road engineering that I see is poorly thought out and does not have the intended effect. People seem to get used to humps. (I've recently discovered how to take humps at normal speed.) And I am convinced that speed cushions reduce safety by not reducing speed but focussing a driver's attention on the small bit of road ahead of them to the detriment of other road users. Poorly phased lights on main roads encourage people to use side streets for rat running.

Oh dear, I'm ranting again aren't I? Hi dee ho.
Road safety advert inaccuracies - blank
At the risk of flogging a horse while it is receiving
last rights ...
Avoidance should be the primary goal as an aware and responsible
driver should never get into the situation shown in the advert.
It's about matching speed to road conditions.
My concern is that there are some people who think that
the solution to all road accidents is to slow traffic to
less than 20 mph regardless of road conditions etc. Then we
will end up with roads that are barely navigable due to
absurd limits, road humps that increase pollution and noise and which
damage and slow emergency vehicles, ill phased traffic lights that increase
pollution, road constrictions that direct cars into cyclists and are used
by some as slaloms and other nightmares.


Absolutely agree! Rather than brainwashing people into thinking that they must be safe if they are driving at the speed limit!

Road safety advert inaccuracies - PhilW
It's very difficult to disagree with the vast majority of sentiments in these posts but surely the point is that they had a 30 second ad to get a simple message across - that braking distance (generally) increases with speed and a pedestrian stands more chance of not being hit/killed if you are travelling more slowly. You could spend hours explaining the the variations on this ABs/carbon brake discs/reaction time/condition of road etc but the simple message is what counts. Even the choice of 30 and 35 mph may just be convenient - the speed is irrelevant - in this case 20 is "safer" than 25, 40 "safer" than 45 etc in that you are more likely to stop in a given time at the lower speed than the higher. It's like the message on fag packets "Smoking kills". Should I say that's daft because it didn't kill my mum even though she had a fag every year after her christmas dinner? Or it's less likely if you don't inhale?
Road safety advert inaccuracies - GJD
It's very difficult to disagree with the vast majority of sentiments
in these posts but surely the point is that they had
a 30 second ad to get a simple message across -
that braking distance (generally) increases with speed and a pedestrian stands
more chance of not being hit/killed if you are travelling more
slowly.


The point is that the message is confused and neither interpretation sensibly promotes safety.
Even the choice of 30 and 35 mph
may just be convenient - the speed is irrelevant - in
this case 20 is "safer" than 25, 40 "safer" than 45
etc in that you are more likely to stop in a
given time at the lower speed than the higher.


By reductio ad absurdum, that argument leads to 0mph being the safest speed. I know you aren't advocating that and I know the ad isn't advocating that.

If the numbers are not chosen purely for convenience, then the significance of 30mph as a speed limit is being dangerously overstated since 30 may well be too fast in a busy high street.

The seatbelt ad and the "don't drink and drive then overtake a cyclist without looking for oncoming traffic" ad are short and hard-hitting without suffering from this sort of flawed reasoning.