Field Testing of Proposed Tridem Truck/Triaxle Trailer Configurations 2001-01-2709

In February 2000, The Insurance Corporation of British Columbia (ICBC) completed the field testing and safety review of three new and two existing logging truck configurations. The three new configurations featured tridem-drive tractors pulling triaxle pole trailers (including a tridem drive straight truck) hauling long or short log loads. The British Columbia logging truck industry has been an enthusiastic proponent of tridem-drive vehicles and combinations for three main reasons: the configurations allow greater log load carrying versatility (easy switching between hauling a single long log load to multiple bundles of short log loads); higher payload capacity than the existing tandem drive tractor with triaxle pole trailer configuration; and, enhanced traction on steep off-highway grades than tandem drive tractors.

ICBC developed a test plan to investigate the dynamic on-highway performance of the new configurations based on the results of a computer simulation. ICBC selected an independent professional engineer to carry out the tests. The tests took place in the first week of February 2000 and included tests of dynamic stability, on-highway performance, and low-speed control on slippery surfaces. For comparison purposes, two existing configurations were tested along with the new configurations.

The new tridem drive tractor configurations met our safety expectations in the tests and showed the computer simulation results to be conservative. The drivers reported that the new tridem configurations felt stable during the test sequences and maneuvers.

The field tests provided concrete assessment and confirmation on the safety of the new vehicle combination. Complied test data and technical references were listed.