The maximum gross weight that may be carried upon any combination of units is limited by the maximum gross weight that can be carried upon each unit and its axles. The maximum gross weight for the unit of tractor and first semi-trailer is governed by this formula: 35,000 pounds plus 1,000 pounds per foot between the center of the foremost axle of the tractor and the center of the rearmost axle of the first semi-trailer. The gross load on a unit may not exceed the sum of the allowable gross loads on the axles, which are as follows:
Maximum gross weight on any one axle | 22,400 pounds |
Tandem axles on one vehicle (under ten feet apart) (Axles measuring less than 46 inches between axle centers are considered as one axle.) | 36,000 pounds |
The limit of 127,400 pounds permitted under 700 CMR 7.08(4) requires a minimum axle spacing of 92 feet, measured betwee n the center of the foremost axle of the tractor and the center of the rearmost axle of the rearmost semi-trailer. If the axle spacing is less, the permissible gross weight is correspondingly reduced.
After all of the component vehicles in a large tandem unit are completely hooked up, and prior to the departure of the large tandem unit from the assembly area, the operator, or a mechanic, shall, in addition to the pre-trip equipment inspection and use requirements set forth in 49 CFR 392.7 and 49 CFR 392.8, inspect the large tandem unit and make certain tests on the vehicle, equipment, and hook-up to determine whether each item is in safe and proper operating condition.
The items to be inspected and tests to be made include, but are not to be limited to, the following:
-Federal equipment inspection.
-Inspection of brake line to dolly and trailers.
-Inspection of electric lines to dolly and trailers.
-Inspection of coupling devices.
Following this inspection and prior to departure from the assembly area, the operator shall complete and execute a tandem trailer inspection report form provided by the Department. A new inspection report must be prepared each time the component parts of the tandem trailer unit are rearranged, or the operator is replaced, or upon re-entry to the Turnpike after any valid departure. The operator shall keep an original inspection report in an accessible place in the vehicle for which it was prepared, and this original inspection report must be presented to an official or employee of the Department, or a Massachusetts State Police officer on demand.
700 CMR, § 7.08