Vehicle Traction Experiments on Snow and Ice

Abstract

<div class="htmlview paragraph">Traction <b>tests</b> were run during February, <b>1993</b> and <b>1994.</b> The snow tests were conducted at a fairly constant temperature of <b>-2°C</b> and the ice tests at an air temperatures ranging <b>from</b> -4 to <b>-35°C.</b> The test vehicles were a standard midsize automobile and highway maintenance gravel trucks.</div> <div class="htmlview paragraph">The automobiles on packed snow at <b>-6°C</b> has <b>an</b> average braking force coefficient of <b>0.35,</b> a lateral force coefficient of <b>0.38</b> and a traction force <b>coefficient</b> of <b>0.20.</b> The corresponding values for a straight truck are: <b>0.23, 0.35</b> and <b>0.15. An</b> automobile on bare ice at <b>-6°C</b> has <b>an</b> average braking force coefficient and lateral force coefficient of <b>0.09,</b> and a <b>traction</b> force coefficient of about <b>0.08.</b> The valves for the truck on bare ice in the same order are <b>0.06, 0.07</b> and about <b>0.04.</b></div> <div class="htmlview paragraph">A relationship was developed between the average braking force coefficient, ambient temperature and the amount of standard highway winter aggregate <b>used</b> on the road. The influence of winter aggregate on ice gave an improvement of about <b>15</b> percent <b>at a</b> highway maintenance light application of <b>75 gm/m<sup>2</sup></b> and about 30 percent at a heavy application rate <b><i>of</i> 150 gm/m<sup>2</sup>.</b></div> <div class="htmlview paragraph">Aggregate blow off tests on bare pavement <b>estimated</b> that at an application rate of <b>175 gm/m<sup>2</sup></b> about <b>100</b> cars or <b>30</b> trucks would remove most of the winter aggregate <b>from</b> a bare road <b>surface.</b></div>