Yet another van almost on its side

[Jeff-Pontypridd]

Nearly every time I listen to 5 Live's traffic reports, I hear of an overturned caravan indident.

Does anyone compile cause statistics for these accidents, that we can learn from. Could the clout of PC get hold of some information for us. Let's learn from others' mishaps, eh?

 

[Lutz]

Paul, if it's feet off everything, then why do electronic stabilisers such as the Trailer Stability Programme fitted to Vauxhall Astras and similar units in BMW X5's, VW Touaregs, Merc M-Class (and probably others by now) apply the brakes of the towcar when the caravan starts to sway?

I've got a LEAS electronic stabiliser fitted to my caravan and it's impossible to provoke a deliberate snake because as soon as sideways sway is detected, it applies the brakes on the caravan. (The LEAS unit works on the same principle as electronic stabilisers in cars but applies the brakes on the caravan instead).

 

[ProfJohnL]

Hello Jeff,

Radio traffic reports are a very biased selection of incidents and cannot be used to give a fair indication of the relative frequencies of any particular type of activity.

It is sad fact that when a caravan is damaged it is usually quite spectacular and that attracts undue attention which makes it newsworthy. The aftermath also take longer to clear up so the relative effect of the incident has a greater impact on the delays.

I am not sure if the police categorise incident data that could be used to retrieve the information about frequencies, but I suspect there are so many variable factors that it would require some very detailed analysis to bring forth any meaningful results.

 

[Lutz]

In over 40 years of motoring I've probably seen 3 or 4 overturned caravans but a good many more other accidents. I therefore doubt whether caravans are involved in proportionately any more accidents than their share of total traffic on the roads. I strongly suspect that if they are reported more often then it's probably because they make a better news story, especially if there are more of the likes of Jeremy Clarkson working for the media.

 

[DEANO3528]

I too find your comments hard to believe Lutz, but if it works for you then so be it that's great. I don't know of many caravans that are heavy enough to apply the brakes whenthe engine goes into over-run unless they were overloaded, although I am prepared to be happily proved wrong. However for those of us, who buy older cars because it's all that we can afford or like me, prefer to be in charge of the car rather than the other way around the advice then would surely be fatally flawed. You also didn't mention this new fangled stabiliser in your original post mate, which would surely be a key factor in sway recovery. I agree that the best way to recover a snake is to brake the trailer, but cannot see how you could do this safely with the towing vehicle by braking without exacerbating the snake you are trying to recover!

There's a bit more ammo for debate.

 

[Lutz]

It's easy, Deano. In the case of cars equipped with ESP+, as soon as a sensor detects sideways movement of the back end of the car that shouldn't be there (such as in the case of the caravan starting to snake) the electronics apply the brakes of the car. Because the caravan is then on the overrun, its brakes too are applied and the outfit will stabilise itself again.

In the case of caravans fitted with the LEAS electronic stabiliser, the same happens only this system is independent of the car's brakes being applied. The sensor is installed in the caravan and, here again, if it detects the caravan swaying, it applies the brakes of the caravan through a electromechanical release mechanism acting on the brake cable. As soon as stability is restored, the system returns to its standby mode.

 

[DEANO3528]

No no, that's not what I meant, but it really is a brilliant aid, and should be std on all new 'vans. I was actually pointing out that while you can safely brake no matter what is going on behind (and the added confidence this must give you can only be good) Paul & Ruth might have a less sophisticated rig, especially being as they stated, relative newcomers. Say a 1995 Passat with a 1990 Eldiss Whirlwind (all off the top of my head here). They get in a snake and do as you told them and chances are they will get on the radio too. Any stabiliser will help, although I don't use one myself yet, but the tried and tested snake recovery of holding the wheel firmly while taking all feet from the pedals allowing the rig to come back under full control has to be the best policy wouldn't you agree?

Damn good topic though, eh?

 

[Lutz]

I agree with you Deano, that it's important to hold the wheel firmly and not to try to steer out of a snake. (In theory it would be possible to steer but you'd have to turn the wheel in the correct direction at precisely the right moment. However, chances are that in such a panic situation you're very likely at some stage to steer out of phase with the snake, making the whole situation even worse than it already is.)

As regards braking, if the snake has only just started and the caravan is not yet swaying very much, you can usually get by with taking the foot off the accelerator. However, once things get more severe, you'll have no alternative but to brake in order to have a chance of catching the outfit again. In short, taking the foot off the pedal may help but braking will help. Whether braking is done automatically, as in the case of electronic stabilisers, or by physically putting your foot on the brake pedal is really immaterial as the effect is the same.

One very sophisticated development of electronic stabilisers on cars can be found on the new Mercedes M-Class which actually applies the brakes alternately on the left and right hand side, effectively steering the car at the same time as braking.

But even the LEAS system I've got on my caravan is uncanny. I've tried it on a wide open space and was unable to get the caravan to get out of control no matter how violent my movements of the steering wheel were.

 

[Colin_5084674]

Whilst you are correct in holding the steering wheel straight, you are joking if you think you should brake, even gently this would lead the car to decelerate more than the van and could lead it to snake and twist more. The best bet is to decelerate the vehicle, and not brake, if you have an automatic unlucky, as you would need to change down to a lower ratio. Even better don't snake in the first place! The caravan snakes when the critical speed of stability has been exceeded. This could be due to a number of reasons:- Sudden wind direction movement (LGV's etc)travelling through exposed regions, sudden vehicle movement-braking swerving, travelling to fast for the conditions, travelling downhill, poor weight distribution in the van, to name a few. Some of these climatic problems are out of your control, and some are not, so with careful forward planning good observations and anticipation, these problems won't occur. Remember you are towing a caravan so you must be on holiday, why rush!

 

[Lutz]

I'm not joking about braking, Colin. In fact, if you've got one of those new cars with ESP+, they will automatically brake as soon as the car senses a snake, regardless of whether you actively slow down or not. In a recent road test of a VW Touareg towing a caravan, the testers noted that automatic braking following a deliberately induced snake was violent and could even be a hazard to following traffic but its ability to re-establish stability was beyond question.