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October 2011 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Responsible Senior Program Officer: Christopher Hedges Research Results Digest 362 REVIEW OF MEXICAN EXPERIENCE WITH THE REGULATION OF LARGE COMMERCIAL MOTOR VEHICLES This digest presents the results of a follow-on study to NCHRP Project 08-63, "Review of Canadian Experience with Large Commercial Motor Vehicles." The study was conducted by the University of Michigan Transportation Research Institute (UMTRI) with the Texas Transportation Institute (TTI) as subcontractor. John Woodrooffe of UMTRI and Dan Middleton of TTI were co-Principal Investigators. Other authors are Juan Villa of TTI and Manuel Solari Terra, private consultant. SUMMARY weight regulations also include exceptions and special permits based on highway con- The objective of this research was to nectivity or access to specific industrial or review and summarize the most current distribution centers. information on the Mexican experience with The Mexico Bridge Formula is the changes in truck size and weight limits and following: to evaluate the potential applicability to size and weight limits in the United States. The L N major activities involved in this research GVWMX = 870 + 3.66 N + 11 were to investigate truck size and weight N -1 limits in Mexico, determine the concerns of U.S. border states, develop options to ad- where dress those concerns, and conduct Mexico/ GVWMX = maximum gross vehicle weight U.S. analysis to determine what the United (kg), States can learn from the Mexican truck size/ L = distance between extreme axles weight experience. (m), and N = number of axles Truck Size and Weight Limits U.S. Federal Bridge Formula B is the Mexico has been regulating large com- following: C O N T E N T S mercial vehicles since 1980, and since then Summary, 1 significant changes have occurred to the L N maximum allowed size and weight. Many GVWUS = 500 + 12 N + 36 Background, 3 of those changes have been induced by eco- N -1 Assessment of Mexico's Truck Size and Weight nomic or technical reasons, but many others Regulations, 7 where are the consequence of pressure from vari- Potential Impacts on U.S. Border States, 19 ous groups that benefit from larger and GVWUS = maximum overall gross weight heavier trucks. Current Mexican maximum of the group (lb), Mexico/U.S. Analysis, 26 weight and size limits vary depending on L = distance between extreme axles Conclusions, 30 highway classification and vehicle and of the group (ft), and References, 32 axle configuration. Mexican truck size and N = number of axles in the group
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120,000 100,000 80,000 Gross Weight (lb) U.S. 4 axles 60,000 MX 4 axles 40,000 U.S. 5 axles MX 5 axles 20,000 0 20 24 28 32 36 40 44 48 52 56 60 Outer Bridge Measurement (ft) Figure 1 Comparison of U.S. Federal Bridge Formula B and the Mexico Bridge Formula. Figure 1 shows that the bridge formula used in loaded to Mexican truck weights. The gross weight the United States is more restrictive than the bridge of cargo and equipment is not allowed to exceed formula used in Mexico to establish maximum GVW the allowable permitted axle load, the Mexican limits. legal weight limit, or 125,000 lb, whichever is the lowest weight. The dimensions of the load and Concerns of U.S. Border States vehicle cannot exceed 12 ft wide, 15 ft 6 in. high, or 110 ft long. The states that border Mexico do not have substan- To reduce the number of crossings at the U.S./ tial concerns about Mexican truck size and weight Mexico border, Texas and Arizona are proposing limits exceeding U.S. limits simply because of the initiatives to allow one of the Mexican long combi- extensive inspection process conducted by both the nation vehicles (LCVs) (T3-S2-R4) with two 40-ft states and the federal government at border inspection trailers to cross into the United States. The proposed facilities. However, there are concerns about the long initiative would allow trucks to cross the border, go queues of northbound trucks waiting to be inspected. through the Customs and Border Protection (CBP) Air quality and noise concerns arise because of trucks and state safety inspections as a combination vehicle idling or creeping slowly and unproductive driver with two trailers, and then travel to a staging yard time waiting for the inspection. where the trailers would be decoupled. From there, Texas and Arizona are either planning or have two power units would pull the two single trailers to implemented three initiatives that can mitigate the their destinations on U.S. roadways. The main ben- effects of Mexican truck size and weight limits that efit of this proposal is the reduction in the number of are being felt along the U.S./Mexico border. The trips at international border crossings where current three initiatives allow trucks to exceed the allowable operations are congested. weights and dimensions under special permitting as The Arizona Department of Transportation described below. (ADOT) has implemented a single trip overweight The overweight corridor program operating be- permit, which allows a motor carrier transporting tween the Port of Brownsville, Texas, and the Vet- fresh produce within the Mexico/Arizona commercial eran's International Bridge--Los Tomates allows zone to lawfully operate a vehicle with an overall trucks to haul break bulk steel and other cargoes gross vehicle weight of up to 90,800 lb on a five-axle 2