This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Dry Pavement Friction Reductions Due to Sanding Applications
Abstract:
The importance of friction applications in the field of
collision reconstruction is well recognized in published research.
However, tire-road frictional drag values (μ-values) are partially
dependent on the surface on which the tire is travelling. One such
variable may be the intentional presence of sand upon a particular
roadway. Sand is sometimes applied to dry pavement in an effort to
absorb liquid debris that may have been accidentally spilled onto
the surface. Once the sand has been applied, it may be left for a
measureable time until the fluid has been absorbed. If a collision
were to occur on that particular surface while the sand is in
place, it may be difficult to determine an appropriate μ-value for
the given scenario.
In an attempt to examine the extent of friction reduction for
both a passenger vehicle and a commercial truck on such a surface,
testing was performed in a like condition. For both vehicle types,
full braking with an active Anti-Lock Brake System (ABS) was used
to measure the respective average and dynamic μ-values. For the
testing, a 2006 Freightliner Century Class tractor pulling a fully
loaded semi-trailer was compared with a 2007 Ford Crown Victoria
automobile.
Test conditions consisted of a baseline dry asphalt surface, a
surface of loose sand, a surface of packed sand, and finally a
surface whereon there was a residual amount of sand. During the
test runs, the vehicles were instrumented with recording devices to
measure the relative acceleration and test speeds. In performing
these tests, it was found that the application of sand did reduce
the pavement friction as suggested in prior research concerning
similarly covered road surfaces. However, it was also found that
while the performance results varied significantly between the
tractor semi-trailer and the passenger vehicle on dry pavement,
their net braking abilities were much closer after the sand was
applied.