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Suggested Citation:"Chapter 4 - Conclusions." National Academies of Sciences, Engineering, and Medicine. 2010. Review of Canadian Experience with the Regulation of Large Commercial Motor Vehicles. Washington, DC: The National Academies Press. doi: 10.17226/14458.
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Page 52
Page 53
Suggested Citation:"Chapter 4 - Conclusions." National Academies of Sciences, Engineering, and Medicine. 2010. Review of Canadian Experience with the Regulation of Large Commercial Motor Vehicles. Washington, DC: The National Academies Press. doi: 10.17226/14458.
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Page 53

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Truck size and weight regulation is abstruse, complex, highly technical, and has multiple close linkages with road- way, pavement and bridge design, construction, maintenance and management, road safety, road capacity and congestion, energy, emissions, rail transportation, and others. The public at large simply does not like trucks, and especially does not like the concept of a larger or heavier truck, whether or not they would know what that would actually entail and what the benefits may be. So making rational changes to truck size and weight in the United States is both technically and polit- ically challenging. The essential lessons learned from the Canadian size and weight experience are as follows: 1. There was national agreement among stakeholders that Canadian size and weight regulations were inconsistent and outdated, which contributed to cross country trans- port inefficiency. Recognition of this problem provided a clear focus for action. 2. A formal body, including federal and provincial govern- ment representation, was established to develop and over- see the process of rationalizing size and weight policy based on scientific analysis. The basis for technical input was the Vehicle Weights and Dimensions Study, which was specifically conducted to provide scientific input. 3. The size and weight study provided an understanding of vehicle infrastructure interaction and produced a set of ve- hicle performance metrics that were used to specify vehi- cle configurations that had desirable vehicle dynamic characteristics and could operate within the load capabil- ity and geometric constraints of the road network. 4. The study also validated the tridem axle group that is the cornerstone upon which many of the higher productivity vehicles are built. 5. Canadian policy is structured through weight allowance limits to provide an incentive for the development and use of vehicles with favorable dynamic characteristics. 6. A formal body was established to oversee the implemen- tation of harmonized size and weight policy among the provinces, and it continues to monitor and respond to needs as required. 7. Size and weight regulation needs to be thorough and com- prehensive so that the desired outcomes are achieved and undesirable outcomes are prevented. There is a need for monitoring of the fleet as it evolves to ensure that undesir- able vehicles are kept in check and that the objectives of the policy can be fully achieved. 8. The Canadian experience points to the simultaneous achievements of productivity, safety and environmental effects—aspects that are sometimes viewed as trade-offs. The U.S. federal government has not made significant change to its truck size and weight regulations since 1991, when it moved to limit the opportunity of states to make changes. Nevertheless, since then, states have continued to make changes that allow larger and/or heavier trucks on roads that are not part of the national network, and these changes have increased the diversity of regulations across the nation. This has created a condition not unlike what existed in Canada before it began its size and weigh harmonization effort. Furthermore, having frozen the federal size and weight policy for the past 19 years as other countries have progressed and made refinements to policy, the United States can benefit from the experience of these other jurisdictions by developing instruments that have proven records of success. In the United States, federal, state, local, toll road and maybe other agencies have authority to set, monitor, and en- sure compliance to truck size and weight limits. It would seem practical to identify one or more ranges of gross weight above 36,287 kg (80,000 lb), define new configurations to address each gross weight range, and require these vehicles be allowed on national network roads that were suitable for them. Canada has three ranges of allowable gross weight higher than 36,287 kg (80,000 lb), essentially for trucks with 6, 7 and C H A P T E R 4 Conclusions 52

8 axles. If a U.S. jurisdiction were to consider a higher allow- able gross weight, it would be appropriate to define weight ranges and vehicle configurations for each. This approach could potentially reduce the number of trucks by maybe 10% to 15%, by judicious definition of weight ranges and suitable vehicle configurations. U.S. specifications are highly influenced by the Federal Bridge Formula, which tends to define the number of axles in a vehicle, the allowable weights, and overall length. There is the potential for an approach based on the bridge formula that could result in undesirable outcomes for vehicles with 6 or more axles. Unless otherwise prohibited, it is likely that lift axles would flourish, which would be threatening to the infrastruc- ture. The approach in Canada was to provide a complete spec- ification for the vehicle, including internal dimensions critical to both infrastructure and vehicle dynamic performance. When truck size and weight regulations are changed, it is not uncommon for industry to find a loophole that provides an unintended, and possibly undesirable, outcome. The ve- hicle configurations that arise from the change should be monitored carefully, and if unintended vehicles with undesir- able infrastructure impacts or dynamic performance are ap- pearing, a mechanism should be available to close the loop- hole quickly to prevent these vehicles becoming common. Dimensional compatibility is more important than the same allowable weights. Jurisdictions should respect the di- mensions agreed upon for the specified vehicle, so that it can travel freely among the jurisdictions that have adopted it. If jurisdictions agree to accept a configuration, they may wish to allow less restrictive dimensions than the specification, but they should not have any more restrictive dimensions. In ad- dition, if the jurisdictions have different allowable axle group weights, or allowable gross weight, the configuration should be able to be loaded to its allowable gross weight in each ju- risdiction within the allowable axle loads and internal dimen- sion limits. Canada’s process developed a performance-based method to assess the dynamic performance of vehicles, and this method was used as the basis for the national configurations, and has been used subsequently by all provinces when considering new configurations, either for regulation or for special permits. This is applied rigorously by all provinces, and it is not uncommon that proposed new configurations are rejected due to deficien- cies in their dynamic performance. On the other side, if a new configuration can be shown to have better, or at least no worse, dynamic performance than existing vehicles it might replace, this provides a strong argument against those who oppose higher weights “on principle.” Grandfather rights and state permit programs allow for a variety of vehicles, some with evidently undesirable effects on infrastructure, dynamic performance, or both. If the federal government, a state, or region would define configurations with greater allowable gross weight and more range, the di- verse configurations operating under grandfather rights and permit programs would simply disappear. Any carrier want- ing to continue to operate vehicles under the old grandfather right or permit program could continue to do so, but most of these local use vehicles would quickly be replaced by vehicles with greater range that would be more efficient. The United States, Canada, and Mexico are equal partners in NAFTA. The NAFTA treaty identified that truck size and weight regulations were potentially a barrier to trade, so it pro- vided a mechanism for the three partners to harmonize their truck size and weight regulations. The United States has essen- tially not made any changes to its size and weight regulations since NAFTA became effective, while Canada and Mexico have both continued to develop their own truck size and weight reg- ulations, which coincidentally have many similarities and con- siderable domestic benefit. Harmonization with the NAFTA partners, to the extent possible, with the intent of achieving more uniform transportation efficiency within North America could present a compelling argument for change. 53

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Review of Canadian Experience with the Regulation of Large Commercial Motor Vehicles Get This Book
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TRB’s National Cooperative Highway Research Program (NCHRP) Report 671: Review of Canadian Experience with the Regulation of Large Commercial Motor Vehicles examines the process used in Canada to harmonize heavy truck size and weight regulations across the country. The report provides insights on how lessons learned from the Canadian experience might be applied in the United States.

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