Field Testing of Proposed Tridem-Drive Tractor/Semi-Trailer Configurations

In October 2000 ICBC oversaw the field testing of two new tridem-drive tractor/semi-trailer configurations: one tridem lowbed semi-trailer, and the other a tridem hayrack semi-trailer. The lowbed configuration was tested with the aim of establishing heavy-haul permit conditions, and the hayrack with the intention of introducing the configuration into the regulations as a new logging truck combination for the province. The British Columbia logging truck industry has been an enthusiastic proponent of tridem-drive vehicles because these vehicles allow greater versatility and payload capacity than the industry currently enjoys, and they provide greater traction than tandem-drive trucks on steep off-highway grades.

ICBC drafted a test plan designed to evaluate certain key handling characteristics of the proposed configurations, particularly dynamic stability. ICBC selected an independent Professional Engineer to prepare a finalized test plan and carry out the testing. The tests took place between October 24-27, 2000 and included tests of dynamic stability, on-highway performance and low-speed control on slippery surfaces.

Both new vehicles passed the tests they were subjected to. The drivers reported that the vehicles felt stable during driving. ICBC has developed new permit conditions and regulations for the tested configurations.