Trailer rules welcomed in Mexico

Feb. 1, 2004
NOT everyone in Mexico agrees with the new trailer and semi-trailer regulations that became effective in December, but almost everyone agrees they were

NOT everyone in Mexico agrees with the new trailer and semi-trailer regulations that became effective in December, but almost everyone agrees they were necessary, according to Salvador Saavedra, a trailer manufacturer consultant in Mexico.

“As with any other standard published in Mexico, there are always people and organizations for it and against it,” says Saavedra, who also is a representative for Canada's KG Industries from Canada, a distributor for Trucklite.

“In this case, most of the people I have been in touch with — manufacturers, importers of new trailers, suppliers, transportation companies, and associations — agree with the fact that it is good to have a standard, though they may not agree with all the requirements included in it.”

On Dec. 23, the NOM-EM-010-SCFI-2003 “Safety Requirements for Trailers and semitrailers” was published in the Diario Oficial (Official Gazette), effective December 24.

For the first time in Mexico, a standard sets the safety requirements that this equipment must comply with. Previously, there were standards for tires, conspicuity tapes, and weights and dimensions, but none for trailers, including brakes, lights, etc.

Saavedra says the primary thrust of the new regulations deals with the Weights and Dimensions Regulation, which allows much higher weights in Mexico than those allowed in the US.

He says that in Mexico, the load that can be carried on a tandem axle of a trailer is 44,000 lb, while in the US it's just 34,000 lb (29.4% higher). The limit for a tandem axle of a tractor in Mexico is 49,500 (45.6% higher). The result is a substantially higher allowable payload in Mexico, as tractor plus tandem-axle trailer plus payload may be as heavy as 107,800 lb (34.8% higher). However, most of the difference in weight (27,800 lb) is payload, thus the trailers need to be stronger, and so do their load-bearing components, such as axles, suspensions, wheels and tires, preferably with the same safety factor as in the US.

“The next issues are the road and geographic conditions. Most of the roads that connect the high-altitude cities with the coastline cities are windy and not well-maintained, so they impose additional stresses to the vehicles, which again requires stronger load-bearing components. Brakes are applied more often, and axles travel up and down frequently, so air consumption is higher than on average US roads. Both Bendix and Haldex have always recommended the use of bigger air tanks to prevent accidents on those roads, a practice currently being followed by most of the Mexican trailer manufacturers.

“Other requirements are not load-related and follow requirements established on the FMVSS, so compatibility in North America is maintained, where possible.”

NAFTA history

Saavedra says that before NAFTA, a permit from the Commerce Department in Mexico was needed to import trailers. As NAFTA was negotiated, it was agreed that no permits would be needed to import new trailers starting in 1995 and the same would apply to used trailers starting in 2004. Trailers manufactured in the US for the Mexican market after 1995 were designed and built strong enough for the tougher Mexican conditions.

He says that as a result of these differences, a trailer built for Mexico is heavier and may carry much more payload than a similar one for the US market. In 2001, the Mexican trailer manufacturers associated with the CANACINTRA (Mexico's National Association of Manufacturers) started the procedures to promote a standard for trailer safety.

“Their objectives were to prevent the market from being flooded with cheap used trailers not suitable for the Mexican roads and regulations and to assure that the trailers imported into Mexico (new or used) as well as those produced locally meet a minimum of safety requirements considering the allowed weights, road conditions, and geography specific to our country,” he says. “The standard was published in the form known as ‘Emergency Standard’, since the deadline for its release (January 1, 2004) did not allow to complete the standard as a definitive one. The standard as published will be in place for a period between six and 12 months while the definitive one is finished following all procedures by law.”

Some US companies are concerned that the trailers they are shipping to Mexico will not meet the standard. Saavedra says this is an issue.

“An ‘Emergency Standard’ is effective the next day of its publication in the Diario Oficial, so it sometimes creates problem for those products being manufactured or in transit to be sold,” he says. “Negotiations are taking place between local manufacturers, importers of new trailers, and the authorities to allow for a period of time to enforce the standard as their inventories are utilized. It is foreseen that an agreement will be reached soon. Everyone agrees that used trailers not meeting the standard should not be allowed for importation into Mexico.” He said that the standard can be obtained, in Spanish only, at

Here are some of the specifics:

  • Axles for air ride suspensions should have a minimum of 5/8" wall and 30,000-lb rating.

  • Axles for spring suspension should also have 5/8" wall but can have a 25,000-lb rating.

  • Suspension capacity should be at least the same as axle capacity.

  • Wheel capacity should be minimum of 7,700 lb.

  • Tires should be NOM stamped.

  • Air brake tank(s) capacity should be at least 11 times the capacity of the service brakes for trailers with air- ride suspensions or eight times for trailers with spring suspension.

  • Brake valves must meet FMVSS-121.

  • Service air brake lines should be 1/2" OD minimum, and colored blue. Supply lines should be 3/8" OD minimum, and colored red.

  • Air brake chambers should have a minimum of 30 square inches, and 2½" stroke.

  • 2S1M ABS minimum is required.

  • Automatic slack adjusters are mandatory.

  • Lights required for dry vans: two yellow front clearance lamps; four red tail lamps; two red stop lamps; two rear red turn signal lamps; three red rear clearance lamps; one white license plate lamp; three clearance lamps per side (one yellow at the front, one yellow at the middle, and one red at the rear); two marker lamps per side (one yellow at the middle and one red at the rear); one yellow turn light at the middle per side. Combinations allowed: two tail lights may also be stop lights; two tail lights may also be turn signal lights if they are red; Middle yellow markers may also be turn lights; front clearance yellow lamp and front side yellow clearance lamps may be one per side if located on the top corner and visible from either the front or the side. Reflective tape should meet Mexican standard NMX-D-225-1996-SCFI.

  • Specification plate should be metallic with the following data: name of manufacturer including address and phone number; trademark; manufacturing date; country of origin; VIN meeting NOM-EM-009-SCFI-2003; vehicle weight; gross vehicle weight rating (GVWR); gross axle weight rating (GAWR) indicating tire size and inflation pressure; dimensions in meters: length, width, height.

The manufacturer of a new vehicle must deliver to the trucking company a letter stating all the data mentioned in the specifications plate as well as a statement assuring that the vehicle complies with all of the specifications mentioned in the standard, which could be verified anytime during the life of the vehicle.

About the Author

Rick Weber | Associate Editor

Rick Weber has been an associate editor for Trailer/Body Builders since February 2000. A national award-winning sportswriter, he covered the Miami Dolphins for the Fort Myers News-Press following service with publications in California and Australia. He is a graduate of Penn State University.