Hi All

I am conducting an investigation into a traffic accident and want to get an idea of possible speeds the vehicle will have been travelling at the time of the accident.  Briefly a left hand drive Mitsubishi Fuso Canter box truck turned a right corner (about 90 degrees) and accelerated (it is assumed at a "normal" rate - i.e. not erratic or excessive speeding). Road conditions were excellent, clear sunny day no other vehicles on the road.  After 130m the vehicle offside (passenger / left side) wheels mounted the kerb and the vehicle collided with a trailer parked on the side of the road 20m further along from where the vehicle mounted the kerb.

So my question is: If the vehicle was travelling at lets say 10 km/h when it entered the road what speed could it have been travelling at in 130m distance when it hit the kerb.  I do not have a time between the two points but am assuming steady (or "normal") acceleration.  Does 50km/h sound reasonable?  is it possible the vehicle could have been going faster (50, 60, 70 or 80 km/h)?

Thanks in advance

Peter

Originally Posted by: A Kurdziel

Assuming its about 10 ms-2 which is about the acceleration due to gravity (1g) we could have a final velocity of only about 21 km/h but the final velocity would have been much higher at a higher acceleration.

10m/s2 (if sustained) would give you a 0-100kph time of under 2.8 seconds, which is a smidgeon quicker than Porsche say the quickest 911-derivative can do it (https://www.porsche.com/uk/models/911/911-gt2-rs/911-gt2-rs/ ).  I think we can safely say that's outside the range of normal for a Mitsubishi truck.

I get 51m/s, or 184kph (114mph) for accelerating at 10m/s2 from 10kph over 130m

But I don't think maths is going to answer the question - it's too ill-defined.  If it's possible that it was going at 50kph, it's probably possible also that it was going at 60kph.  Assuming starting at 10kph and accelerating at constant rate, a final speed of 50kph implies accelerating at 0.713m/s2, and 60kph implies 1.04m/s2.  I don't see any way of saying one of those is possible and the other is not.

A one litre manual Ford Fiesta can do 0-100kph in 10.5 seconds, so that's average 2.78m/s2, so the two cases above are between about one quarter and one third of fiesta-with-pedal-to-the-metal case.  They are probably possible, but I'd guess that's working an emptyish truck quite hard.  I don't see any way of quantifying whether that's normal-for-a-mitsubishi-truck.

But this is based on knowledge of physics, not knowledge of trucks.

I'd ask to see his phone records...