damn, that sucks about the car.
Hope it works out for you OK. I actually ended up ahead when I totalled my 240, ended up with a newer one and cash from parting the other out.
Anyways, as far as the speed the 280 was going, you dont need any braking specs.
Sorry if this reminds you too much of high school physics, but heres the Mechanical Engineer in me speaking.
When a cars in a skid, that means the wheels are locked up, and the only thing stopping the car is the sliding friction between the tires and the road. However, it is very difficult to get the speed he was going because of two problems. First, the speed you would get is the speed he was going when his wheels locked, which is after he first started braking. Second, you would have to assume he was pretty much stopped at the point of impact and that it was only friction stopping him and not you car.
Well, anyways, heres the equation based on those assumptions I derrived.
Vo = sqrt(2*s*u*g)
Where:
Vo = his speed in ft/s (multiply by .682 to get miles/hr)
s = distance of skid (should be the length of the mark, but subtract out the wheelbase of the car if all 4 wheels were locked)
u = coefficient of kinetic friction ( I searched and saw this page, it says to use 0.8,
http://www.sciencejoywagon.com/physics....ion.htm )
g = graviational acceleration (32.2 )
Anyways, I came out with only 24.3 miles/hr if the length you gave is the full length of the skid.
Again, thats the speed he would have been going when the wheels locked and if he was barely moving at the time he hit you.
if you can estimate how fast he was sliding at impact, then you can have a better estimate. I think you would actually just add that on.
Well, sorry for rambling on, but figure Id share with ya.
Good luck,
Greg