Professional' Truck Drivers 5194Adrian your have I have never in 10 years of driving an HGV (but mostly part time to be fair) ever hit another vehicle in a normal RTI...
Quite simple really. Without the skid marks you cannot know where the driver started to brake and you cannot therefore know the distance over which the car was slowing or at what rate.
That buttumes that the driver applied maximum braking force and actually produced skid marks. You need to know the rate of deceleration and without knowing the amount of braking pressure you cannot.
Even *with* skid marks it doesn't mean that the start of the marks is the point that the driver started to brake.
Why not? Without knowing the prior free running speed you cannot know whether the car was 'speeding'1. If you cannot know whether the car was speeding you cannot say that the accident was caused by 'speeding'. These are indisputable facts yet the anti-speed lobby produce loads of statistics that rely on a single piece of information that cannot be know. All of their statistics that use data from accidents where the prior free running speed is not know are therefore meaningless.
But has nothing to do with calculating the prior free running speed.
1 except in the case where the impact speed is calculated to be higher than the speed limit.
-- Mark Foster, Brighton, Suslove, UK PGP Fingerprint: 3342 C02C 7BE8 3FE4 AAC5 8BB2 03B7 9263 DDF2 04C1 -------------------------------------------------- "There are no such useless words as...'I didn't have a chance.'" Driving, HMSO
