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15 ary highway, which did not have the pavement strength for 2.1.7 Influence of the North American full M.o.U. loads. Their designated highway systems therefore Free Trade Agreement excluded these lower strength highways, though M.o.U. con- figurations were allowed to operate on them, but at weights The Free Trade Agreement between Canada and the United lower than those prescribed by the M.o.U. Qubec designated States became effective in 1988, and was superseded by NAFTA its primary highway system, but initially only allowed B-trains in 1994. Previous to these agreements, it was effective for a U.S. up to a gross weight of 58,500 kg (128,969 kg) and an overall manufacturer to maintain a branch plant in Canada to manu- length of 23 m (75 ft 6 in.) off divided highways, generally facture products, which were then distributed east and west because of the geometry and condition of the primary highways across Canada from the branch plant. After free trade, it became in the northern part of the province. The Atlantic Provinces more effective for the manufacturer to maintain the most effi- generally designated their primary highway systems, with cient plant, whether in the United States or Canada, and to significant weight restrictions on other highways, primarily distribute the products to the other country as necessary. because of the large numbers of older bridges with inadequate Within a relatively short time, as branch plants closed, a sig- or unknown capacity. nificant amount of east-west freight transportation in Canada Since 1989, Alberta has designated essentially its entire changed to a north-south orientation. A consequence was that highway system at M.o.U. loads. Other provinces have added the importance of harmonization among Canada's provinces highway links on the basis of demand for service and after tended to decrease, and the importance of harmonization upgrades to roadway, pavement and bridges. At this point, between Canada's provinces and their neighboring U.S. states while M.o.U. configurations certainly cannot use all roads in increased. This was felt most strongly in Ontario, as 60% of all provinces at their full M.o.U. loads, they can go essentially all Canada's imports and exports pass through Ontario. everywhere they need to go at those loads, and can go almost The 16.2-m (53-ft) semitrailer became the standard semi- everywhere at whatever reduced load is specified for the roads trailer in the United States. within a couple of years after pas- involved. sage of the M.o.U., just as the freight pattern was changing The provinces took different approaches to adopt the from east-west to north-south. Again, as with the 14.65-m M.o.U. British Columbia, Alberta, Saskatchewan, and Mani- (48-ft) semitrailer after the STAA in 1982, there were difficul- toba simply adopted the M.o.U. as their size and weight reg- ties as some carriers brought 16.2-m (53-ft) semitrailers into ulation, and they grandfathered existing noncompliant con- Ontario, while others moved freight destined for Canada into figurations at their existing weights for a specified period. 14.65-m (48-ft) semitrailers before crossing the border. The Ontario initially adjusted its rules in 1989 to allow M.o.U. Ontario Trucking Association built a strong coalition of ship- configurations without restriction up to a semitrailer length pers, carriers and others in support of 16.2-m (53-ft) semi- of 14.65 m (48 ft) and an overall length of 23 m (75 ft 6 in.). trailers. A study identified that the 14.65-m (48-ft) length It finally increased the semitrailer length to 16.2 m (53 ft), and limit was costing Ontario Can$100 million annually in addi- the overall length of doubles to 25 m (82 ft), in 1994, and tional transportation costs (39). Ontario then finally accepted defined these vehicles as specific configurations subject to this length for semitrailers, and the 25-m (82-ft) overall all the dimensional limitations of the M.o.U. Qubec was length for double trailer combinations in 1994. The M.o.U. unable to make changes until Ontario had set its regulations was finally amended with the semitrailer and overall length and, in 1991, amended its dimensions to allow M.o.U. con- changed to the original agreed-upon lengths of 16.2 m (53 ft) figurations at the same restrictive lengths as Ontario, made and 25 m (82 ft), respectively, in July 1994. Qubec and the other changes to ensure M.o.U. configurations would not be Atlantic Provinces immediately facilitated 16.2-m (53-ft) semi- restricted, and reduced the allowable gross weight on A-train trailers and 25-m (82-ft) B-trains by special permit, and sub- doubles to the M.o.U. value of 53,500 kg (117,946 lb). The sequently put them into regulation at these lengths. Atlantic Provinces initially allowed the M.o.U. configurations as additional configurations, but subsequently in 2001, in 2.1.8 Amendments to the M.o.U. since 1988 concert, adopted the M.o.U. and grandfathered existing configurations (37). The CCMTA/RTAC Vehicle Weights and Dimensions When provinces implemented the M.o.U., they took diverse Study defined a standard process for assessing the dynamic approaches to noncompliant vehicles from other jurisdic- performance of vehicles against base performance standards tions that arrived at their borders. Some simply rejected the that were objectively related to highway safety (18), (33) and non-compliant vehicles and others allowed them a trip per- Appendix D. The M.o.U. defined vehicle configurations for mit to deliver their current load. Qubec developed a restric- tractor-semitrailers and A-, B- and C-train doubles with dimen- tion on semitrailer wheelbases for tractors with a wheelbase sions and allowable weights on the basis of this process. How- over the 6.20 m (244 in.) limit in the M.o.U. (38). ever, each province also had a range of other configurations,

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16 Figure 15. M.o.U. straight truck. Figure 17. M.o.U. truck-pony trailer combination. principally for truck-trailer combinations. Collectively, the met the dimensional constraints for a B-train as defined in the provinces asked, now that tractor-semitrailers and doubles M.o.U. However, the combination had substantially greater had been configured to ensure they met objective standards offtracking than the largest tractor-semitrailer allowed under for dynamic performance, should other vehicles also be con- the M.o.U., so a restriction to limit the sum of the wheelbases figured in a similar manner? of the two semitrailers of a B-train to 17.0 m (55 ft 9 in.) was The range of straight trucks and truck-trailer combinations also introduced in the 1991 amendment. was defined, and the dynamic performance of these vehicles The M.o.U. initially limited the gross weight of C-train dou- was assessed by computer simulation using the same meth- bles pending clear definition of the desired properties of a ods as used during the CCMTA/RTAC Vehicle Weights and C-dolly. These were developed in a subsequent study (41), Dimensions Study (40). This identified that the truck hitch supported by federal safety standards for the dolly (42) and its offset, trailer wheelbase and trailer drawbar length were sig- hitches (43). Features of this work were added into the C-train nificant parameters. A limited test program was conducted to specification in the M.o.U.; its allowable gross weight was verify the variations in performance measures due to varia- increased to 58,500 kg (128,969 lb), and its box length was tion in these parameters (40). From this work, configurations increased to 20 m (65 ft 7 in.) when the M.o.U. was amended in for a straight truck, shown in Figure 15, a truck-full trailer, 1991. It had become clear by this time that the B-train was the shown in Figure 16 and a truck-pony trailer combination, configuration of choice for heavy loads, and that the C-train shown in Figure 17, were defined. These configurations, and was simply a means for carriers, mostly in the Prairie Provinces, a 14-m (46-ft) long intercity bus, were added to the M.o.U. in to get a useful payload out of specialized trailers originally built the first amendment in 1991. The front axle weight of a as an A-train and modified to become a C-train. straight truck was restricted to 5,500 kg (12,125 lb), the same The second amendment to the M.o.U. was made in July as the allowable front axle weight for a tractor, due to con- 1994, when the semitrailer length was increased to the origi- cerns about flexible pavements primarily in Saskatchewan. nally agreed upon length of 16.2 m (53 ft), and the overall The four Western Provinces immediately adopted the new length of double trailer combinations was increased to the configurations. originally agreed upon length of 25 m (82 ft). It also included An early proposal was made for what was essentially a jeep two clarifications, as follows: dolly to pull a 14.65-m (48-ft) semitrailer, a combination that A dromedary box may be used to carry load on a tractor, and A B-train may use a tridem axle group on the rearmost semitrailer. The third amendment to the M.o.U. was made in June 1997, and consisted of minor changes to simplify and rationalize details of the M.o.U. The following amendments were made: The box-length limit for truck-pony trailer and truck-full trailer configurations was increased to 20 m (65 ft 7 in.), primarily for compatibility with the so-called Maxi-cube truck-pony trailer combination introduced into U.S. reg- Figure 16. M.o.U. truck-trailer combination. ulations (44);