As of July 1, Ontario will allow longer wheelbase tractors for single, tandem and tridem semi-trailer configurations.

The Ontario Trucking Association praised the measure. "The configurations MTO has moved forward on represent approximately 85% of the trailer fleet operating in Ontario," said OTA President David Bradley.

The change is designed to accommodate environmental devices and add-ons, OTA said, and that is essential in reducing greenhouse gases. The Ministry of Transportation's turning-performance standards and all other HTA dimensional criteria are also met under the new rules.

Under the change, the maximum allowable tractor wheelbase will increase from 6.2 meters (244 inches) to 7.2 meters (282 inches) for vehicles classed as SPIF1 (Safe, Productive and Infrastructure Friendly) Designated Tractor-Trailer Combinations: single, tandem and tridem tractor/fixed axle semi-trailer configurations, OTA explained in a press release.

For longer tractors, MTO is using an already established formula from other jurisdictions that reduces trailer wheelbase as tractor wheelbase increase, which allows the configuration to negotiate turns the same as any other vehicle. All other Canadian provinces allow for a longer wheelbase tractor, save for Nova Scotia which requires a special permit.

OTA said it has begun work with MTO to determine the feasibility of allowing longer wheelbase tractors on other SPIF configurations including tri-axles, quad-axles, five, six-axle and B-train configurations.

New exhaust aftertreatment devices, auxiliary power units and the like have been impinging on frame-rail space typically reserved for fuel tanks, air supply tanks, batteries and other equipment, OTA, says, and emerging technologies like hybrids and natural gas vehicles could make frame-rail space even more of a premium.