DOT offers Congress its size and weight scenarios The Dept. of Transportation has issued the first comprehensive size and weight study in almost 20 years. The report, which has been rendered in completed chunks over the past several years, has been pilloried already in some trucking quarters by those who have attacked its methodology and data.
ATA president Walter McCormick said in a prepared statement: "The study is flawed and should not be used as the basis for highway safety decisions. Instead of relying on sound science and research data, the study is based on vehicle configurations that have never been used, running on unrealistic highway networks in states where longer-combination vehicles don't operate."
Despite its detractors' opinions, the report represents the most comprehensive work thus far on size and weight. The four-volume, one-and-a-half-inch-thick report is designed to be a guidepost for Congress, offering five scenarios for lawmakers to study when considering national size and weight legislation. None of the scenarios is touted as the best, and DOT officials say that additional options, including hybrids of those offered, may be advanced and analyzed as the discussion ensues.
Here are brief summaries of the scenarios:
- Uniformity. This would eliminate current grandfather provisions that allow some states to retain higher GVW and axle limits than federal limits now in place on Interstate highways. Federal limits would be extended to the entire national network, resulting in uniform weight limits.
- NAFTA. This scenario focuses on enhancing trade among NAFTA-member nations and other international trading partners, and puts U.S. trucks on par with GVWs in Canada and Mexico. One effect would be to allow heavier weights on certain configurations by increasing allowable tridem-axle loads to be consistent with those in Canada and Mexico.
This limit also would allow transportation of international containers loaded to ISO limits. For example, 97,000 lb. for six-axle tractor-semitrailers; 71,000 lb. for four-axle single-unit trucks; and 131,000 lb. for eight-axle twin-trailer combinations with 33-ft. trailers. Current grandfathered limits would stay in effect.
- LCVs nationwide. LCVs currently operate in one form or another in 20 states; by law, this number has been frozen to states operating them before June 1, 1991. This scenario assumes LCV operations on the national network. One provision proffers that turnpike doubles (twin 53-ft. trailer combinations weighing up to 148,000 lb.) and Rocky Mountain doubles (combinations with one 53-ft. trailer and one 28.5-ft. trailer weighing up to 120,000 lb.) would not be allowed to leave the network because of their relatively poor maneuverability. They would have to use staging areas to assemble and disassemble. Triple-trailer combinations (28.5-ft. trailer weighing up to 120,000 lb.) and eight-axle twin-trailer (combinations with two 33-ft. trailers weighing up to 124,000 lb.) would be allowed to travel off the network because of their better maneuverability.
- H.R. 551. This scenario studies the Safe Highways and Infrastructure Preservation Act, introduced in 1994 and again in 1997, that federalizes some truck regulations that are now under state control. Specifically, it would phase out trailers longer than 53 ft., freeze state grandfather rights and freeze weight limits on non-interstate portions of the National Highway System.
- Triples nationwide. This possibility would permit triple-trailer combinations having three short (28- to 28.5-ft.) trailers to operate at the same weights and on the same designated highways as the LCV-nationwide scenario.
The scenarios are played out against their effect on freight diversion, cost to infrastructure, safety, government cost, shipper and trucker costs, traffic management, environmental quality and energy use.
While Congress is chewing on this, DOT is moving ahead with another study mandated by law. This study will consider whether changes in size and weight limits actually are advisable, based on how they affect the economy, safety, environment and services to communities.