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lower GVWs. Spreads of this nature are generally prohibited in the western Canadian Provinces. They do not classify as a tandem axle, and are not permitted to operate as two single axles. British Columbia has at times required the wheels to be removed from one of the axles, to render the semitrailer a single axle unit. Alberta allows only a single axle load on the two axle group. Manitoba prohibits their use, although from time to time allows them by permit for one trip.

Differences in tire load limits among the ten western jurisdictions have no significant effect on western border trucking. Most trucks are provided with enough tires and tire width to ensure that the applicable axle limit is reached before the tire limit. At the 500 pounds per inch limit, four 10- inch tires (two sets of dual tires) on a single axle can handle a load of 20,000 pounds, the limit for a non-steering single axle. Eight 10-inch tires on a tandem axle can handle 40,000 pounds based on tire load limits, but only 34,000 pounds based on the tandem axle load limit. The exceptions are: (1) Saskatchewan regulations prohibit the effective use of wide-base tires by limiting the load on an individual non-steering tire to 6,600 pounds, (2) British Columbia has the same restriction applicable to RTAC Memorandum of Understanding trucks, and (3) Alberta prohibits the use of wide-base tires on tridems.

Tridem axle load limits in Washington, Idaho, Montana, North Dakota (only on the IS), and Minnesota are governed by Bridge Formula B. On non-IS highways, North Dakota allows a tridem axle load of 48,000 pounds irrespective of spread. Canada's tridem limits are 23,000 kilograms (50,600 pounds) or 24,000 kilograms, depending on spread. Alberta prohibits the use of tridems with wide-base tires.

Canada's steering axle limit of 5,500 kilograms causes problems at certain crossings. U.S. vehicles entering Manitoba from I-29 can come in with a steering axle load of as much as 6,000 kilogram, and are required to move their fifth wheel to comply with the 5,500 kilogram requirement. Some of these vehicles have probably had their load shifted to the steering axle to remove weight from the drive tandem. In Manitoba, they then must shift weight back to the drive axle. Alberta seldom experiences a problem in this regard and generally does not require adjustment if it occurs.


Western border States, except Minnesota, limit vehicle height to 14 feet. This is 6 inches more than allowed in the western Canadian Provinces. Fourteen-foot vans are used throughout the western United States particularly by specialized truckload carriers (California can manufacturers and paper product manufacturers in Idaho and Oregon). Other areas benefitting from the 14-foot height limit include handling high cube 9-foot, 6-inch containers and stacking three flatdeck trailers. Some but not all Alberta enforcement officers allow 14-foot units to enter the Province under a grandfather right.

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