Hard Shoulder - Wheels to Left or Right?

[pingu393]

I've searched the site and not found anything related to +hard +shoulder +wheel


A long time ago (20 years+) I did a seminar about motorway recovery. We were told...

1. Park as far over to the LEFT as possible about 10 metres behind the casualty parallel to the road.
2. Turn the wheels to full LEFT lock.

The reason was that if my vehicle was hit, it would be shunted OFF the carriageway.


I'm now seeing more and more RAC and AA type vehicles (people I assume have been trained) parking on the RIGHT of the hard shoulder and pointing slightly LEFT. Their wheels are turned to the RIGHT.

I can see the benefit of the parking position as it gives maximum protection to the people in front, but why are the wheels pointed towards the carriageway? Have things changed?

Comments please.

[Frik]

I'm no expert, but I would have thought that the idea behind point the wheels towards the carriageway would be that cars on the motorway have the chance to avoid a vehicle projected onto it, whereas those parked on the hard shoulder don't.

[voicey]

Not sure about the way the wheels should be pointing but I was once told that it is best to park at an angle when pulling up behind an incident as it looks different to all the other moving cars and thus people take more notice of the stationary vehicles.

[R0G]

The fend off vehicle should have the front end pointing to the right but the wheels pointing to the left

If another clips the fend off vehicle on the side then they may be deflected back towards the carriageway but if the fend off vehicle is hit from behind then the wheels move it away from the carriageway

[pingu393]

Thanks for that. I like the logic of what ROG says. Makes sense to me.

[Hooli]

R0G said:

The fend off vehicle should have the front end pointing to the right but the wheels pointing to the left

If another clips the fend off vehicle on the side then they may be deflected back towards the carriageway but if the fend off vehicle is hit from behind then the wheels move it away from the carriageway

I think the idea of the fed off vehicle pointing to the left nowdays is to make it harder for the inattentive sleeping polish lorry driver to take the mirrors off.

[cosicave]

ROG is correct.

In addition to his very good post, there are two further benefits to parking at an angle: it increases the view of the emergency vehicle presented to approaching traffic, together with a psychological benefit; instinctively most people will steer wider of a vehicle if the first impression is that it looks as if it may be about to pull out.

[Hooli]

[quote=cosicave]ROG is correct.

[quote]

I'm not saying he isn't, his post makes sense.

I just know what we tended to do with coaches & trucks in laybys to save on broken mirrors so mentioned it.

[Vaux]

pingu393 said:

I can see the benefit of the parking position as it gives maximum protection to the people in front, but why are the wheels pointed towards the carriageway? Have things changed?

Comments please.

I don't understand why the wheels are turned in any direction. If you're hit by a 44t artic you're going to move in the direction the LGV struck you? The front tyres will simply slide over the road surface.

If you're hit by something smaller, will the physics be any different? Is there a situation where the front wheels will actually steer the vehicle?

[RenesisEvo]

Vaux said:

If you're hit by something smaller, will the physics be any different? Is there a situation where the front wheels will actually steer the vehicle?

The front wheels (normally - Saab etc) aren't held by the handbrake. It takes a lot less energy for the wheel to start rolling than for it to slide across the surface, so the front wheels will turn when the vehicle is struck, which will impart steering on it. Imagine putting your car on full lock, then getting out and pushing it - it will turn. I guess if you hit it hard/fast enough it might slide but something would have to stop the front wheels rotating in order to cause them to slide. For the back wheels the handbrake does that job (to a point).

[cosicave]

Hooli said:

[quote]

I'm not saying he isn't, his post makes sense.

I just know what we tended to do with coaches & trucks in laybys to save on broken mirrors so mentioned it.

Yes, I know that Hooli. I did not mean to appear to criticise your post at all. I think it is just the chronology of the thread which may have led you to that conclusion, if indeed that was your conclusion.

[BertBert]

I suspect that the direction the front wheels are pointing will have little effect.

Without anyone steering, the vehicle will be steered by the impact. Just like a shopping trolley.

Bert

[X8Matt]

Please forgive the tedious lecture...

During the impact event itself, the significance of any friction or otherwise due to the direction of the front wheels will be neglible. After the impact, the vehicle (what is left of it!) will then coast along in whatever direction its wheels take it.

The direction of the vehicle during and immediately after the impact depends on exact location of the impact. If the impact is in line with the centre of mass of the vehicle then it will travel in a straight line. More likely, the impact will be to the right of the centre of mass, causing it to rotate counter clockwise in the plan view - i.e turn left.
Try it next time you are in the supermarket with an empty trolley. Give the centre of the handle a shove and the trolley will go straight ahead (then veer off as the castor wheels will do whatever they want!). Shove the right hand side and it will turn left.

Hope this helps...

Matt

[R0G]

BertBert said:

I suspect that the direction the front wheels are pointing will have little effect.

Without anyone steering, the vehicle will be steered by the impact. Just like a shopping trolley.

Bert

The steering would be locked in the direction the wheels are facing unless the ignition is on I think

[Hooli]

cosicave said:

Hooli said:

[quote]

I'm not saying he isn't, his post makes sense.

I just know what we tended to do with coaches & trucks in laybys to save on broken mirrors so mentioned it.

Yes, I know that Hooli. I did not mean to appear to criticise your post at all. I think it is just the chronology of the thread which may have led you to that conclusion, if indeed that was your conclusion.

Ahh, noted. All is well once more

[pingu393]

Police seem to be parking...

At a slight angle facing left, with wheels turned left, with about a metre of space between the right rear bumper and the main carriageway.

The front of the car was as close as possible to the left of the hard shoulder without having to reverse to move forward when they set off on full right lock.

I saw two like this yesterday.

[mph1977]

voicey said:

Not sure about the way the wheels should be pointing but I was once told that it is best to park at an angle when pulling up behind an incident as it looks different to all the other moving cars and thus people take more notice of the stationary vehicles.

i think the theory with the recovery vehicles and wheel facing 'out' is two fold

1. they don't strictly 'fend off' in the way I and most other people who do any kind of emergency services work would understand it - they tend to sit square to the running lanes rather than sweeping across to come to rest at 30 - 45 degrees to the running lanes

2. there have been quite a few recovery guys crushed or killed by their own vehicle coming up the verge when hit from behind and the wheels facing 'in'project the vehicle along the hard shoulder and up the verge

[BertBert]

R0G said:

The steering would be locked in the direction the wheels are facing unless the ignition is on I think

I think rather pedantically that the ignition has to be on or it has been on and the key not subsequently removed.

However, if the driver who has parked on the HS is relying on the wheels pointing in a certain direction, the ignition lock being on would be helpful.

Bert

[Pontoneer]

I note that the Police in my area (Strathclyde) always park some distance behind the incident , nose-in slightly towards the side of the road and with wheels on full lock in the same direction - my interpretation being that , if struck from behind , the police vehicle would be shunted off to the side and not where people are working/trapped .

I work for the Fire Service and our vehicles adopt the 'fend-off' position : this involves parking nose-out towards the centre of the road ( incidents sometimes take place on the right side of the road ) to deflect any errant vehicles away from the incident ; a fire appliance weighing anything upwards of 20 tonnes is less likely to be shunted far by an impact ( unless it is hit by another HGV ) .