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52 CHAPTER 4 Conclusions Truck size and weight regulation is abstruse, complex, 6. A formal body was established to oversee the implemen- highly technical, and has multiple close linkages with road- tation of harmonized size and weight policy among the way, pavement and bridge design, construction, maintenance provinces, and it continues to monitor and respond to and management, road safety, road capacity and congestion, needs as required. energy, emissions, rail transportation, and others. The public 7. Size and weight regulation needs to be thorough and com- at large simply does not like trucks, and especially does not prehensive so that the desired outcomes are achieved and like the concept of a larger or heavier truck, whether or not undesirable outcomes are prevented. There is a need for they would know what that would actually entail and what monitoring of the fleet as it evolves to ensure that undesir- the benefits may be. So making rational changes to truck size able vehicles are kept in check and that the objectives of and weight in the United States is both technically and polit- the policy can be fully achieved. ically challenging. 8. The Canadian experience points to the simultaneous The essential lessons learned from the Canadian size and achievements of productivity, safety and environmental weight experience are as follows: effects--aspects that are sometimes viewed as trade-offs. 1. There was national agreement among stakeholders that The U.S. federal government has not made significant Canadian size and weight regulations were inconsistent change to its truck size and weight regulations since 1991, and outdated, which contributed to cross country trans- when it moved to limit the opportunity of states to make port inefficiency. Recognition of this problem provided a changes. Nevertheless, since then, states have continued to clear focus for action. make changes that allow larger and/or heavier trucks on roads 2. A formal body, including federal and provincial govern- that are not part of the national network, and these changes ment representation, was established to develop and over- have increased the diversity of regulations across the nation. see the process of rationalizing size and weight policy This has created a condition not unlike what existed in Canada based on scientific analysis. The basis for technical input before it began its size and weigh harmonization effort. was the Vehicle Weights and Dimensions Study, which Furthermore, having frozen the federal size and weight policy was specifically conducted to provide scientific input. for the past 19 years as other countries have progressed and 3. The size and weight study provided an understanding of made refinements to policy, the United States can benefit from vehicle infrastructure interaction and produced a set of ve- the experience of these other jurisdictions by developing hicle performance metrics that were used to specify vehi- instruments that have proven records of success. cle configurations that had desirable vehicle dynamic In the United States, federal, state, local, toll road and characteristics and could operate within the load capabil- maybe other agencies have authority to set, monitor, and en- ity and geometric constraints of the road network. sure compliance to truck size and weight limits. It would seem 4. The study also validated the tridem axle group that is the practical to identify one or more ranges of gross weight above cornerstone upon which many of the higher productivity 36,287 kg (80,000 lb), define new configurations to address vehicles are built. each gross weight range, and require these vehicles be allowed 5. Canadian policy is structured through weight allowance on national network roads that were suitable for them. limits to provide an incentive for the development and use Canada has three ranges of allowable gross weight higher of vehicles with favorable dynamic characteristics. than 36,287 kg (80,000 lb), essentially for trucks with 6, 7 and
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53 8 axles. If a U.S. jurisdiction were to consider a higher allow- Canada's process developed a performance-based method able gross weight, it would be appropriate to define weight to assess the dynamic performance of vehicles, and this method ranges and vehicle configurations for each. This approach was used as the basis for the national configurations, and has could potentially reduce the number of trucks by maybe 10% been used subsequently by all provinces when considering new to 15%, by judicious definition of weight ranges and suitable configurations, either for regulation or for special permits. This vehicle configurations. is applied rigorously by all provinces, and it is not uncommon U.S. specifications are highly influenced by the Federal that proposed new configurations are rejected due to deficien- Bridge Formula, which tends to define the number of axles in a cies in their dynamic performance. On the other side, if a new vehicle, the allowable weights, and overall length. There is the configuration can be shown to have better, or at least no worse, potential for an approach based on the bridge formula that dynamic performance than existing vehicles it might replace, could result in undesirable outcomes for vehicles with 6 or more this provides a strong argument against those who oppose axles. Unless otherwise prohibited, it is likely that lift axles higher weights "on principle." would flourish, which would be threatening to the infrastruc- Grandfather rights and state permit programs allow for a ture. The approach in Canada was to provide a complete spec- variety of vehicles, some with evidently undesirable effects on ification for the vehicle, including internal dimensions critical infrastructure, dynamic performance, or both. If the federal to both infrastructure and vehicle dynamic performance. government, a state, or region would define configurations When truck size and weight regulations are changed, it is with greater allowable gross weight and more range, the di- not uncommon for industry to find a loophole that provides verse configurations operating under grandfather rights and an unintended, and possibly undesirable, outcome. The ve- permit programs would simply disappear. Any carrier want- hicle configurations that arise from the change should be ing to continue to operate vehicles under the old grandfather monitored carefully, and if unintended vehicles with undesir- right or permit program could continue to do so, but most of able infrastructure impacts or dynamic performance are ap- these local use vehicles would quickly be replaced by vehicles pearing, a mechanism should be available to close the loop- with greater range that would be more efficient. hole quickly to prevent these vehicles becoming common. The United States, Canada, and Mexico are equal partners Dimensional compatibility is more important than the in NAFTA. The NAFTA treaty identified that truck size and same allowable weights. Jurisdictions should respect the di- weight regulations were potentially a barrier to trade, so it pro- mensions agreed upon for the specified vehicle, so that it can vided a mechanism for the three partners to harmonize their travel freely among the jurisdictions that have adopted it. If truck size and weight regulations. The United States has essen- jurisdictions agree to accept a configuration, they may wish tially not made any changes to its size and weight regulations to allow less restrictive dimensions than the specification, but since NAFTA became effective, while Canada and Mexico have they should not have any more restrictive dimensions. In ad- both continued to develop their own truck size and weight reg- dition, if the jurisdictions have different allowable axle group ulations, which coincidentally have many similarities and con- weights, or allowable gross weight, the configuration should siderable domestic benefit. Harmonization with the NAFTA be able to be loaded to its allowable gross weight in each ju- partners, to the extent possible, with the intent of achieving risdiction within the allowable axle loads and internal dimen- more uniform transportation efficiency within North America sion limits. could present a compelling argument for change.