Differential Vehicle Incidents
While travelling on snow-covered icy roads, drivers of two tractor trailers engaged the driver controlled differential lock to allow the unit to run on a single set of tire chains on the rear axle. The drivers also engaged the inter-axle differential lock. This differential lock requires slippage in order to travel through a turn. In both incidents the vehicles could not make the curve or corner and drove into the ditch causing significant damage to the vehicles.