Massachusetts Cop Forum banner
1 - 1 of 1 Posts

4,172 Posts
coefficient of friction


this information is from "traffic accident reconstruction" by lynn b. fricke, northwestern university traffic institute, 1990: isbn 0-912642-07-6; library of congress #90-60196: (62-14)


dry: wet:
new- 0.80 to 1.00 0.50 to 0.75
travelled: 0.60 to 0.70 0.45 to 0.65
traffic polished: 0.55 to 0.65 0.45 to 0.60

these values vary and depend upon the speed of the vehicle. there are further values in the book for pedestrians, or for vehicles on concrete, gravel, ice, snow, etc. also for motorcycles. trucks (commercial) are different: the tire composition is "harder" and when articulated vehicles are involved, there are several factors (such as degrees of freedom) that affect the vehicles "f" value.

in short, always try to determine the coefficient of friction using a drag sled, vc 2000, or similar devices at the scene! book values should be your last resort.

if you need to build a drag sled (it is cheap, so relax) goto order "design, creati...y event, so much for an easy answer... :lol:
1 - 1 of 1 Posts