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
(19,068 kg) for a tri-axle. Some states may allow a tri-axle load of 60,000 lb (27,240 kg) on the semitrailer
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.