Assessment of the vulnerability to strandings of vehicles on compacted-snow road surfaces

<p>We conducted a vehicle starting experiments in which the drive wheels were inserted into a pit created on a compacted-snow road surface. For each type of vehicle, we determined the pit depth on the compacted-snow surface, which is the boundary between the occurrence and avoidance of stranding (the minimum pit depth for occurrence of stranding, d_sp). For heavy trucks and combination vehicles, separate experiments on vehicle starting were performed in order to elucidate the mechanism behind vehicle strandings. The results were used to determine the maximum depth of compacted-snow cover at which vehicles remained free from stranding (the maximum non-stranding snow depth, H_smax).</p><p>The following findings were obtained. d_sp was greater for four-wheel-drive passenger cars and combination vehicles, and was the smallest for 2-t front-engine rear-wheel-drive trucks. d_sp was greater when the vehicles were loaded. For heavy trucks, combination vehicles, and 2-t trucks, d_sp increased with drive wheel load. Additionally, d_sp was found to increase linearly with increase in the outer diameter of the drive wheel. For heavy trucks, d_sp did not necessarily decrease significantly when only the middle drive wheel (between the front wheel and the rear wheel) got stuck in the pit on the compacted-snow surface. In case of a semi-trailer stuck in the pit on the compacted-snow surface, d_sp for combination vehicles was markedly lower.</p><p>Our results lead to the determination of the value of H_smax, which is expected to be utilized as an index value for more adequately implementing preventive road closures and early snow removal.</p>