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29 the origin and destination were both in Canada, or both in the sponsible for 0.61% of all trips, only between Ontario and United States. This excluded about 15.72% of all cross-border Michigan. trips from this analysis. The four western provinces each replaced their previous reg- A total of 154 distinct configurations were found making ulations with a set of regulations that were based directly on the cross-border trips during the 1999 National Roadside Sur- M.o.U. The only significant variation was that British Colum- vey (65). bia allowed 24,000 kg (52,910 lb) on any tridem spread from The top ten configurations accounted for 92.45% of all trips, 2.44 to 3.70 m (96 to 146 in.), whereas the other three provinces and coincidentally included all configurations that individually used the loads specified in the M.o.U. These provinces all took contributed more than 1% of the total number of trips. Seven a principled approach to vehicles entering from other juris- of the top ten configurations were specified in the M.o.U. The dictions, which were principally from or through neighbor- other three were the tri-axle semitrailer that was widely used in ing U.S. states. Vehicles that did not meet the new regulations the six eastern provinces, the quad-axle semitrailer that was in these provinces were denied entry. Consequently, the widely used in Ontario and Qubec, and a 9-axle A-train fleets in these provinces have not been affected by the regula- that was used between Ontario and Michigan. The remain- tions in the various neighboring states. These states, from ing 25 configurations individually contributed between 0.08 Washington to North Dakota, regulate gross weight by an and 0.52% of the total number of trips, and collectively con- uncapped bridge formula, which has tended to result in long tributed 5.89% to the total number of trips. A-train configurations. The M.o.U. excludes these by length, The tractor-tandem semitrailer (T12-2) was the most com- but not necessarily by their gross weight limit of 53,500 kg mon configuration, by a wide margin, in all provinces, and (117,946 lb). However, the form of regulation has allowed these made almost two-thirds of all cross-border truck trips, a pro- states to accommodate M.o.U. configurations, such as tri- portion more than 60% higher than for all trips in Canada. This dem semitrailers and 8-axle B-trains. Tridem semitrailers effectively depressed the proportion of all other configurations. with an added liftable axle operate between British Colum- Two- and 3-axle straight trucks (S11 and S12) were the sec- bia and Washington at a gross weight up to about 45,360 kg ond and fifth most common configurations, and made 9.88 (100,000 lb), and B-trains operate at a gross weight up to and 2.38% of all cross-border truck trips, respectively. These 47,854 kg (105,500 lb). B-trains also operate on limited routes are primarily local use vehicles in both urban and rural areas. within Montana, some at their Canadian weights. The tractor-tridem semitrailer (T12-3) and 8-axle B-train (T12-3-B2) were the third and fourth most common config- urations, respectively, and together they made 4.77 and 3.2.3 Unanticipated Impacts 2.82% of all cross-border truck trips, respectively. The num- 3.2.3.1 Assessment of Dynamic Performance bers of B-trains crossing the borders of the four western of Vehicles provinces from their neighboring states is rather striking. The bobtail tandem tractor was the sixth most common The CCMTA/RTAC Vehicle Weights and Dimensions configuration, responsible for 2.24% of all trips. Study developed the concept that the dynamic performance of The tractor-tri-axle semitrailer (T12-12) was the seventh heavy vehicles could be assessed against objective standards, most common configuration, responsible for 1.29% of all and developed a process for doing this. Several provinces use trips, from Ontario, Qubec, and the four Atlantic Provinces. the performance measures to evaluate vehicles that fall outside These vehicles can operate as a 6-axle vehicle in New York by of the M.o.U. definitions. These vehicles typically run under special permit, and may also cross the border with the liftable special permit programs specifically designed to promote effi- axle raised, carrying a tandem semitrailer load. cient transport. The tractor-split tandem semitrailer (T12-11) was the The M.o.U. configurations and allowable weights were based eighth most common configuration, responsible for 1.21% of strictly on assessments of the performance of vehicles during the all trips from Manitoba eastward. This is a common heavy CCMTA/RTAC Vehicle Weights and Dimensions Study. How- haul vehicle in the United States that is outside the M.o.U. but ever, the M.o.U. addressed only tractor-semitrailers and dou- continues to operate either by trip permit, by accommoda- ble trailer configurations. The regulations of each province tion in regulation, or under old regulations. address all vehicle configurations. After the provinces had The STAA double, with twin 8.53-m (28-ft) trailers (T11- amended their regulations to implement the M.o.U., they all 1-A11), was the ninth most common configuration, respon- had essentially the same question: Now that we know the sible for 0.79% of all trips. This is a U.S. configuration used vehicles covered by the M.o.U. meet objective standards for for light-package freight in the U.S. A 9-axle A-train double dynamic performance, how about all the other vehicles that (T12-3-A111) was the tenth most common configuration, re- are allowed by our regulations? Most of these vehicles were