Although operation aboard Federal Installations may not require permits, operations on public
roads will require permits for loads that exceed the legal highway limits. Each state highway
authority sets its own oversize/overweight limits. In general, operations without permits are
allowed for vehicles that do not exceed 80,000 lb (36,320 kg) Gross Vehicle Weight (GVW).
Any load that exceeds 80,000 lb (36,320 kg) GVW will require a permit. Loads are evaluated
on the basis of the Federal Bridge Formula which provides acceptable limits for weights on
axles and groups of axles. The Bridge Formula allows maximum axle weights of 20,000 lb
(9,080 kg) for a single axle, 34,000 lb (15,436 kg) for a tandem axle, and 42,000 lb (19,068
kg) for a tri-axle. Some states may allow a tri-axle load of 60,000 lb (27,240 kg) on the
M870A3 with the proper permit. Divisible loads are restricted to 80,000 lb (36,320 kg) GVW
and are rarely permitted above that limit.
Before operating on public roads, check applicable state laws with regard to payload, bridge
requirements, and oversized loads, if applicable. Ensure that proper permits have been
received prior to conducting operation on public roads.