Truck turning circle - URGENT HELP PLEASE!

[GreenV8S]

Perhaps not what you want to hear, but by half way through a turn it would not have been obvious whether the truck was going to make it. If you suppose the truck's turning circle is 10% wider than the width, by the time it reached the middle of the road it would only have been six degrees short of square on. Probably not enough to be obvious to the naked eye especially at night. Since the truck actually made an S turn rather than a U turn, you don't know how close to square on it actually got. It could have been miles out and it wouldn't have been apparent half way through, and of course it would have been able to straighten out OK on the other side.

Is it really critical whether the truck could have made the turn in one? I would have thought as long as it looked possible to a sensible and prudent driver it would be OK?

[towman]

I`m assuming that the plod (like me)considered that it would be a slow U turn if you had a horse in the back.

The best the biker would have seen is the orange marker lights down the side (if it has them fitted as it`s an old truck).

Without seeing the exact location, I would have to say that it sounds like a dangerous move.

[Zad]

Well, according to my trigonometry...

With the vehicle parked, left wheels against kerb, full right lock, with a turning circle (diameter, not radius) of 15.8m:

The centre of rotation is sqrt((7.9^2)-(4.35^2)) = 6.6 Metres from the kerbside.

So, if we rotated the vehicle through 180 degrees, assuming the front wheels could ride over the far kerb, would leave the kerb side of the rear wheels 13.2m from where they started.

Mike (working on a simulation)

[falcemob]

This all sounds like the case rests on where the manouvre took place, not whether it was possible to do it in one turn. It's not exactly the cleverest of decisions to do a U turn on a main road at night.
I hope the horse was OK

[B19GRR]

Yep, I have to say I agree with you all. Barring any amazing discoveries today by the lorry owners as they do some test turns and take pics, I think I will not bother presenting this turning circle as evidence and leave it to the jury to decide.

The horse was fine as well, in fact she was happy as Larry the whole journey and only got a bit annoyed when the police car arrived with it's blues flashing. She was even fine when the lorry had to be jacked up to replace the damaged rear tyre. And this is a young ex-race thorugh bred mare who was normally a bit scatty

Thanks all!
Rob

>> Edited by B19GRR on Sunday 24th April 12:00

[HiRich]

Sorry I'm late to this, but basically, theory is pretty useless. There are so many scrub issues with low-speed, high steering angle movement (especially RWD), that you really can't make a decent estimate.
Your best bet is a practical test on a wide open space. It will be quicker and more accurate.

[B19GRR]

Ah well, the result is in already. The first thing the judge said was "why is this a DD charge as according to both prosecution and defence statements, visibility was at least 150yds in both directions which is more than adequate." He then told the prosecution to go and reconsider the charge as careless which the driver had always offered.

Upshot was a guilty plea to careless, 8pts and £850 fine/costs. It was accepted by both sides that the lorry couldn't have made the turn so as I suspected figuring the turning circle never really came in to play. Got to say the driver was incredibly lucky to have got away without a disqualification.

Of interest though is the lorry owners did do some test turns and did get the lorry to do a 180degree turn in a 13.15m space, cunningly confounding all my calculations.

Anyway, thanks for all you help/thoughts, glad it's all over now!

Cheers,
Rob