The Traffic Accident Reconstruction Origin -ARnews-
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The apparatus you are referring to is known officially as the British Portable
Skid Resistance Tester. It is covered by ASTM E303-74 - "Measuring
Pavement Surface Frictional Properties Using the British Portable Tester".
It is also known as the British Pendulum. The device has a rubber slider
mounted on the end of the pendulum which is allowed to swing down in an
arc and contact the road surface to be tested. As the pendulum swings down
it contacts the road surface and some of it's energy is lost. The pendulum
is allowed to complete it's swing, but is caught before it contacts the road
surface again. An indicator shows the height of the pendulum swing, and
from this the energy lost is determined.
This apparatus has limitations, as it tests a very small section of the roadway.
Friction testers built to ASTM 274-85, or skid testing using G-analysts and
Vericoms will return an average value over a much larger area, just like you
get in real life.
I have been using a pickup truck mounted friction tester which meets ASTM
274 and have been very happy with the results.
Randy Baerg
rbaerg@direct.ca
For example, to continue this discussion look for a thread titled
Pendulum Drag Tester
If this thread does not exist in the current archive, you can begin another one by using that title.