Safe Speed Forums

Hi Gerry and welcome

I am inclined to agree with you with regards the term 'accident', it needs to be used carefully and in such a way as it doesn't embed the idea that road traffic collisions are not actually anyone's fault.

I'm not sure that tackling specific identifiable behaviours is the way to improve road safety though. We need to improve driver's attitudes across the board, however with the way society is today I reckon thats one hell of a task. Good driver attitudes demand, amongst others, tolerance to get along with others others and humility to admit mistakes - attributes that seem to be in short supply these days.
I reckon just getting people to take the task more seriously would be a start. Yep, the guy who turned into Tesco's carpark in his people carrier today steering with just the palm of one hand and nearly hitting a parked car as a result - I'm looking at you, you pleb.

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Political Correctness is a doctrine, fostered by a delusional, illogical, liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

There is already an offence that can deal with tailgating - DWDCA or DD.

We really don't need any more laws! But I agree with you, driver education would be a massive step in the right direction...

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Pecunia Prius Equitas et Salus

There's a very simple and effective theme going on. Please indulge me if you will…

A) Identify a demon in our midst
B) Inform us
C) Tell us the cure
D) Make money from our paranoia

E.g.: You are being bombarded with germs. They're everywhere! Although mankind has lived with them for thousands of years and our immune system has served us very well, suddenly, we can't live in this dangerous and hostile environment anymore.

We are told they are ALL bad, using adverts where the germs look evil. Add to this that your house is infected and your children are at great risk! (always helpful to get the kids in there). The germs lurk on door handles and kitchen surfaces, just waiting to get us. The toilet is smothered in them - it's worse than a bear trap in there.

Now then, having sold us the notion, everyone starts buying disinfectants and sprays to 'protect us' and our families from harm. Our immune system is worse than at any other time in mankind's history, but at least we feel safe and secure in our home now - don't we?

Where else can we see this happening?...

The demon? Speed
Inform us (the children are especially at risk)
The cure? Speed cameras, obviously.
And finally - make money from our paranoia.

I rest my case.

There is a demon, called bad driving, and I don't deny it needs to be tackled.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

We all know what the weather's been like recently...

Last night, in the rush hour, on my way home from work (up the M6) on my bike, rain lashing down, I was maintaining a safe stopping distance from the vehicle in front, when I looked in my mirrors and saw a car following me really closely. I squeezed my brake lever gently to just show my brake lights to him, but he still wouldn't back off.

So I slowed down a bit, but he still wouldn't back off. The inside lanes were full of cars and lorries, so I couldn't move out of his way. So I slowed down even more until I was doing about 20mph. He started flashing and tooting me. I swivelled in my saddle and gesticulated to him to back off which he did! Why oh why do knob-head car drivers insist on tailgating, especially in conditions like yesterday?

A biker with less christian-like tendencies than me would stop, pull the driver out of his car and give him a right panning...

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Pecunia Prius Equitas et Salus

I know what you mean BB I have been there many times myself. But you were in a much more vulnerable position than he. I know you were caught between a rock and hard place but making him angrier could have had very different consequences, as I'm certain you know.

Please - I don't want to see you as a patient.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

On this occasion (as I was on my bike and not in the car) I wasn't trying to make him angrier - it really was a case of I had nowhere to go and I needed him to back off. If I'd been in my car, I would have acted differently...

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Pecunia Prius Equitas et Salus

Tailgating is easily defined as "Time interval between vehicles". The Highway Code defines the safe distance between vehicles in tabular form as stopping distances for various speeds. These can be converted to "TBVs" [Time between vehicles] using a 21.5 ft/second squared deceleration rate and a 0.68 second average reaction or thinking time factor. The graph of TBV against speed is a straight line and goes from approx 2 seconds for 20 MPH up to 5 seconds for 100 MPH. The TBV for 70 MPH is around 3 seconds and this will give you enough time to slam on the brake and stop should the vehicle ahead hit a brick wall.
Generally we see the fast line at 80 MPH with TBVs of less than 1 second. It is crazy!
PS: the fastest gun draw in the UK was once 0.4 secs and was held by a woman. No idea what it is now.

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CatsEye

The Highway Code stopping distances are not really representative of modern car capabilities. It is also "unlikely" that the vehicle ahead will hit a wall and stop instantly.

From experience, I still think 2 seconds is a pretty good guide at most speeds an utilises road space quite efficiently.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

Agree, malcolm- from memory these "stopping distances" have changed little (if any) since i passed my test .in those days common cars were the Austin 30/35, Moggie minor /Traveller ans the Hillman Imp. Of course things like Lotus Cortinas /possibly Cooper S had disks on the front( , but even then all tyres were cross plies.Servos ---EH WHAT ???possibly on prestige cars. In the late 70's I bought a Maxi, and took it back to the dealer for some MOT work, to be lent a Hillman Imp - never realised the difference radials and a servo made till then

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

Mmmmh well, I agree initially Malcomw, but then we have to disagree. If there are only one or two vehicles in front then I would agree.

IF it's a whole train of vehicles doing say 70mph.... Then an incident with the first vehicle causing a concertina effect down the line means that the vehicle in front of you CAN indeed stop as though it as hit a brick wall if you are several vehicles back! The further you are back in the line, the BIGGER GAP you need...

TAILGATING?...........YES!.............That's the cause of accidents at whatever speed.... NOT "speed" per say...

And don't forget Malcolm, that Guy 2 secs behind you. when YOU stop dead through hitting the Guy in front of you............his front bumper is going to hit your dashboard!.......

Yes - 2 seconds may well be appropriate at lower speeds and traffic densities; but it should realised that the risk factor rises exponentially as the TBV is reduced.
Also tiredness, boredom and stress should be taken into account which at times would make 4 seconds a better option. You take your pick at your own peril.
As for out of date stopping data it should not be forgotten that the only thing that stops you is the coefficient of friction between the ?slippery road? and a few square centimeters of rubber, however good your brakes. And as for the guy behind. And the one behind him/her. And the one behind him/her Best stop slowly.

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CatsEye

I'm really sorry, but I think this is complete nonsense. I hate to be 'hard' on a new user, but I think this is really important.

We clearly have a duty to drive at such a speed that we know we can stop in the clear distance ahead (a safe speed').

But take a simple case. There are two vehicles. They have similar braking performance. The front vehicle cannot stop instantly, and the driver of the rear vehicle has a responsibility to observe that his full braking distance ahead will be clear if he needs it. In other words he needs to observe beyond the vehicle ahead - preferably far beyond the vehicle ahead. It does not matter AT ALL if a similar vehicle at a similar speed is present within his braking distance so long as he always has time to react to something that the vehicle ahead does.

The Highway Code recommended two second gap has ABSOLUTELY NOTHING to do with braking distance. It has everything to do with time to react for the following driver.

The tailgating that scares me is the tailgating where drivers fail to allow time to react.

Of course the superior driver will adjust his following distance to take account of conditions too. With hazards ahead a longer gap makes sense, and you are able to pass back less braking than the vehicle in front uses. If you are being tailgated you can increase the gap in front to allow for passing back some reaction time to the idiot behind.

Where groups of vehicles are travelling too closely the lack of reaction time means that each needs to brake harder than the one in front which is the main cause of braking waves.

But tailgating is all about insufficient time to react and not-at-all about braking distances.

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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

Sorry Safespeed but I will stick to my guns. The 2 second recommendation is based on the 0.68 sec think time and the balance of 1.32 secs comes from s= ut + 1/2a t [squared] where s is the stopping distance, t is time and a is the deceleration rate.
I do agree that in a two car situation you can drive looking through the lead car's windscreen as it were ; but in the middle of a 40 car queue the situation is very different and the risk of at least one driver failing to react in time is very high.

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CatsEye

No it isn't. (Sorry again.)

It's really based on 'one second's unavoidable distraction' plus one second's reaction time.

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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

OK - enough said and all a bit pedantic. I assume that neither of us has yet been involved in a shunt so what are we getting bothered about? Cheers

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CatsEye

Cheers, indeed!

I hate getting into arguments with new users, but to me, this isn't a pedantic point - it's a vital one. There's a great deal of muddled thinking around and when the concepts of 'safe speed' get muddled with the concepts of 'time to react', I think we (as a nation) need clarity.

I can tell you that I frequently follow at about 1 second, at speeds of 60mph and more without ever getting involved in any kind of incident. Of course I'm not describing normal driving, but I am describing the temporary close following recommended in preparation for overtaking.

I expect you recognise the technique, because I sense that you have an IAM/RoADA/Police driving background. With such backgrounds you are especially welcome here.

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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

and some advanced instructors recommend 3 seconds to allow an additional second for "is this really happening?". The example given was of a bridge collapse with people driving over the edge without even hitting the brakes. Apparently in extreme conditions it's quite common for your thoughts to be "this isn't really happening" rather than "maybe I should hit the brakes".

No - I have no advanced driver qualifications. I'm just a 72 yr old marine engineer with latterly 5 yrs experience as a private hire taxi driver, now retired. However I have spent this time studying tailgating and it's effect on traffic perturbations and have arrived at some interesting conclusions.
Namely: The inverse of mean TBV [Time between Vehicles] equals Traffic Density. Also the probability of a traffic jam is proportional to Traffic Density. Therefore tailgating causes traffic jams. Otherwise how do you explain those Phantom Traffic Jams that appear to have no cause; or those sudden drops in speed in the fast lane?. It is all down to Poisson's queueing theory He was a redoubtable mathematician and actually has the solution to Traffic congestion. But that is another story all wrapped around the concept of the Interactive Catseye. Meanwhile best to back off a bit and we will all have a little less stress; but yes you do have to come up close if you are about to overtake. makes sense doesn't it?

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CatsEye

I don’t believe tailgating per se is a cause of the ‘domino effect’ (the stop/start waves rippling through traffic). If you think about it, if everyone managed to maintain a consistent TBV then the domino effect cannot occur, regardless of actual TBV. The problem is that many drivers don’t keep a constant TBV (or cause others not to with poorly executed lane changes). The worst contributors are those who pussyfoot on the gas so leaving an inordinately large gap in front when pulling away or accelerating back to speed – I see exactly this on the M3(M25) contraflow every frikking day.

The domino effect is also a symptom of lazy drivers who don’t look beyond the rear bumper of the vehicle in front, who then must compensate by over-braking when an unexpected event occurs. These drivers had realised (at some mental level) the fact they had to overcompensate so next time they’ll leave a much bigger gap when building up speed again, hence under-accelerating, thereby amplifying the wave.

I honestly believe the domino effect would cease if everyone applied at least some level of C.O.A.S.T.
A level of decent motorway instruction would be a good start!

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

Braking waves and the resultant traffic jams are a direct result of drivers not leaving sufficient time to react.

If the chap behind brakes a fraction later than the chap in front he has to brake a fraction harder to compensate for the later start. Over about 6 or 8 cars, all with insufficient time to react, gentle braking becomes a full-on emergency stop due to this effect.

Any of us can 'break the chain' by arranging sufficient time to react and braking less than the chap in front by starting to brake sooner.

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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