Code of Massachusetts Regulations › 700 CMR - DEPARTMENT OF TRANSPORTATION › Title 700 CMR 7.00 - Use of the Massachusetts Turnpike and the Metropolitan Highway System › Section 7.08 - Limitations on Large Tandem Units

Current through Register 1525, July 5, 2024
(1)
Scope
. 700 CMR 7.08 applies exclusively to large
			 tandem units.
(2)
Use
			 of Ways
. Tandem units are not permitted in the Tunnels. No
			 operator may operate a large tandem unit on any way other than the Turnpike. An
			 operator may operate a large tandem unit on the Turnpike only if the Department
			 has issued a large tandem unit permit pursuant to
			 700 CMR
			 7.07(2).
(3)
Configuration and
			 Length
. A complete large tandem unit consists of a tractor, first
			 semi-trailer, dolly, and second semi-trailer. The length of either semi-trailer
			 may not be in excess of 48 feet, and the total length of the combination,
			 including the dolly and load, may not exceed 120 feet, provided, however, that
			 the overall length of loaded tandem trailer automobile haulers may not exceed
			 108 feet and may be increased to 109 feet by load overhang.
(4)
Maximum Gross
			 Weight
. A large tandem unit must be registered for the gross
			 weight that it carries and certified by the original manufacturer to carry this
			 weight. The vehicle weight of a large tandem unit may not exceed 127,400
			 pounds. The maximum gross weight of the tractor and first semi-trailer may not
			 exceed 71,000 pounds. The maximum gross weight of each unit of dolly and
			 semi-trailer may not exceed 56,400 pounds.
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.
(5)
Size and Weight Limitations
			 Generally
. The provisions of
			 700 CMR 7.00 with respect to
			 size and weight that are not inconsistent with 700 CMR 7.08(4) are applicable
			 to large tandem units unless specifically excluded under the terms of a large
			 tandem unit permit.
(6)
Approval of Vehicle or Equipment Used to Tow
. The
			 owner or lessee of a large tandem unit must file a description of the tractor,
			 dollies, and any semi-trailer used to tow another semi-trailer with the
			 Department on Forms MTT-3, MTT-4, and MTT-5, respectively. The owner or lessee
			 must obtain the Department's approval of the vehicles before they are used
			 under a large tandem unit permit. The Department may withdraw its authorization
			 to use the vehicles at any time at its sole discretion.
(7)
Certification of
			 Tractors
. No operator may operate a large tandem unit unless the
			 Department has certified that the tractor of the unit is appropriate for the
			 purpose. Both the tractor manufacturer of each tractor used in a large tandem
			 unit and the owner or lessee of the unit must certify to the Department prior
			 to the approval of the tractor that it is capable of hauling the maximum
			 permissible gross load to be transported by the owner or lessee at a speed not
			 less than 20 m.p.h. over the Turnpike. (The maximum grade on the Turnpike is
			 7.50%, and the length of the longest such grade is approximately 1.75 miles.)
			 If it is determined after the tractor is in use as part of a large tandem unit
			 that the tractor cannot meet this requirement, the Department's approval may be
			 withdrawn, and, in that event, the tractor may not be used as part of a large
			 tandem unit on the Turnpike until the gross loads are reduced, the tractor is
			 modified, or other corrective measures are taken. Upon a new certification by
			 both the tractor manufacturer and the owner or lessee that corrective measures
			 have been taken and the tractor is now capable of complying with the minimum
			 speed requirement, the Department may reinstate its approval of the
			 tractor.
(8)
Certification of Trailers
. No operator may operate a
			 large tandem unit unless the Department has certified that the trailer of the
			 unit is appropriate for the purpose. In order to comply with 700 CMR 7.08(13),
			 all semi-trailers, except the rear trailer used in tandem operation, must have
			 sufficient structural strength to permit the satisfactory attachment of the
			 coupling device (pintle hook or its equivalent) at the rear of the trailer, and
			 each coupling device must be capable of towing a trailer and a dolly. The
			 permittee shall certify to the Department that every trailer certified for use
			 in tandem service is adequate for this service and, in addition, the trailer
			 manufacturer on new equipment must certify the adequacy of the trailer. If the
			 trailer has been modified to include a pintle hook, the fabricator must certify
			 the adequacy of the pintle hook assembly. Every coupling dev ice must
			 incorporate a no-slack design such as air take-up, fitted pin and socket,
			 mechanical wedging, or similar coupler designs, that eliminate fore and aft
			 slack in the coupling of dollies to semi-trailers. The no-slack feature of the
			 coupler must be in constant operation while the tandem trailer combination is
			 operated on the Turnpike. The coupler used on each semi-trailer, in conformance
			 with 700 CMR 7.08(8), must be specified by the permittee on Form MTT-4, giving
			 semi-trailer descriptions and the vehicle identification number on the
			 permittee's records (company number) and must be filed with the Department in
			 conformance with 700 CMR 7.08(6).
(9)
Brakes
.
(a)
Compliance with Federal
			 Regulations
. The brakes on a vehicle or dolly converter or
			 combination of vehicles used in a large tandem unit must comply with federal
			 regulations as published in 49 CFR Part 393 , Subpart C, as revised and
			 effective on the date of the vehicle's entry upon or use of the
			 Turnpike.
(b)
Compliance with State Law
. A vehicle or dolly
			 converter or combination of vehicles used in a large tandem unit must meet the
			 requirements of the provisions of the M.G.L. c. 90.
(c)
Braking Devices
			 Required
. The brake application line of every large tandem unit
			 certified on or after June 1, 1968, must be equipped with suitable devices to
			 accelerate application and release of the brakes of the towed vehicles. These
			 devices must be so arranged that the brake application signal does not pass
			 directly through more than one trailer, but is dead-ended at the rear of the
			 trailer or, alternatively, at the dolly, and the application signal then is
			 retransmitted to the dolly and the second trailer. The devices required for
			 retransmission of the application signal must be closely connected to and
			 supplied by air reservoirs that have their air supplied to them by the
			 emergency line. In the event of rupture of the application line on the towed
			 vehicle of a large tandem unit, the loss of brake application must be limited
			 upstream of the loss to those vehicles between the rupture and the first
			 retransmission device.
(d)
Brakes on Steering Axle
. A tractor used in a large
			 tandem unit must have brakes on the steering axle.