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North Dakota [8]

The North Dakota limits specified by the ISTEA freeze for double-trailer combinations are 105,500 pounds GVW and a box length of 103 feet. The triple-trailer combination limits are 105,500 pounds GVW, but a box length of 100 feet. Permits are required to operate at greater than 80,000 pounds GVW on IS highways. These are obtained across the counter for a fee.

Double-trailer combinations at up to 105,500 pounds GVW are common in North Dakota, and in cross border trucking. These combinations are typically used for truckload hauling of special commodities such as grain and fertilizer (using hopper bottom trailers), fuel (in tankers), dry bulk materials (such as cement), and flatdeck trailer operations.

North Dakota does not require trucks to comply with the inner bridge requirements of Bridge Formula B on non-IS highways. The inner bridge requirements are enforced on IS highways, however. In both cases, outer bridge requirements must be met.

North Dakota permits 48,000 pounds on three-axles or more, without reference to Bridge Formula B, on non-IS highways. Tridems on IS highways are limited by Bridge Formula B.

By axle weights, a six-axle tractor-semitrailer is theoretically permitted 94,000 pounds GVW on non-IS highways in North Dakota (12,000 pounds on the steering axle, 34,000 pounds on the drive tandem axle, and 48,000 pounds on the trailer tridem axle). In practice, such a combination would normally gross at about 90,000 pounds because of the Bridge Formula B limitations and the practical outer axle spacing. Six-axle tractor-semitrailers regularly operate on North Dakota IS highways at 88,000 to 89,500 pounds GVW using routine permits and in full compliance with Bridge Formula B.

Bridge Formula B limitations, however, encourage North Dakota trucking to utilize five-axle tractor-semitrailers with 10-foot split tandems, which creates two single axles, to operate at GVWs of 86,000 pounds rather than six-axle tractor-semitrailers at 88,000-90,000 pounds GVW. This is because the extra tare weight of the six-axle unit is about 3,000 pounds, leaving it a payload capacity more or less the same as a five-axle unit with a split tandem.

From an interview with officials at the Emerson Scale on May 30, 1995, it was learned that : (1) there is a growing use of split tandems on crossborder movements on I-29; and (2) Manitoba has grandfathered a limited number of North Dakota carriers to operate vehicles having a tandem axle spacing of 8 feet on the pup trailers in old seven-axle A-train doubles.


As Minnesota has not allowed LCVs or ISTEA CMVs, the freeze does not apply to that State.

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