Inappropriate Connection Leads to Fatality Accident
Updated: Nov 8, 2021
NATM was approached by the National Highway Traffic Safety Administration (NHTSA) in late 2020 following a fatality accident. The incident was the result of many factors, but most especially an inappropriate connection between the tow vehicle and towed unit which led to disconnection on a highway. NATM has worked with NHTSA on numerous occasions to help address areas of concern the agency has identified in both the trailer manufacturing and towing space. It was the hope of NHTSA that NATM could reach out to its industry network and end-users to help provide additional education on proper connections to prevent incidents such as the one described.
There are a number of devices available to hitch a trailer to a tow vehicle, or, in the case of some RV applications, to hitch the motorhome to a towed unit. Examples of hitching systems include ball mounts, gooseneck or fifth wheel couplers, pintle hitches, and tow bars. No matter which type of hitch system is used, the hitch needs to have a capacity equal to or greater than the Gross Vehicle Weight Rating (GVWR) of the trailer or towed unit. For a trailer, the GVWR is listed on the VIN tag. As a general rule of thumb, any towing combination’s maximum capacity is never greater than the lowest rated part in the system.
Even if a trailer is properly hitched and the equipment used is of an appropriate capacity, it is still possible for a component part to fail and potentially detach from the tow vehicle. To help protect against the possibility of complete disconnection, towers should utilize two safety chains or cables connected directly to the tow vehicle and trailer. While state law varies as to the requirement of safety chains, their use is recommended for each and every tow. NATM recommends the following practice:
• Crisscross the chains to form an X beneath the trailer tongue so that it would catch the tongue should the trailer disconnect from the tow vehicle. Only enough slack to allow turning should exist.
• If possible, the chains should be looped back to hook onto themselves.
• Do not hang an S hook on the opening of the receiver hitch, it might bounce off while driving, but loop it through the opening and connect it to the chain.
As with the hitch, safety chains or cables being used, including all components of the chain system, must have a capacity equal to or greater than the GVWR of the towed unit. This means that the chain/cable itself, the hooks which attach to the tow vehicle, and the method of attaching the chains to the towed unit ALL must have a capacity equal to or greater than the GVWR of the towed unit. Further, each chain and each component must be equal to or greater than the GVWR individually, including each individual chain/cable. Do not sum the capacities of the two chains or cables. Imagine an uncoupling; one chain-system would most likely engage before the other, and if the system did not have sufficient capacity in relation to the GVWR, it would be liable to break followed by a breakage in the other chain system. The towed unit would then be disconnected from the tow vehicle.
Consider the following example:
• Trailer GVWR: 5,000 lbs.
• Hook: 7,500 lbs. each
• Chain: 5,500 lbs. each
• Attachment method: 10,000 lbs. each
The weakest link in this scenario is the chains at 5,500 lbs. capacity, which is greater than the trailer’s GVWR, and thus adequate. Remember, each component by itself, must be equal to or greater than the GVWR. Please note, these capacities are dependent upon a properly loaded trailer that does not exceed the GVWR identified by the manufacturer. If the trailer were overloaded, the entire trailer would be at risk of component failure, and the chains in the above scenario may not be adequate to prevent a disconnection. It is vital towers abide by listed weight maximums to ensure a safe tow.
For more information about proper hitching, including the use of the various hitching systems listed, visit www.TrailerSafetyWeek.com/hitching.
To learn more about safe trailering practice, or to join the safe trailering movement, visit www.TrailerSafetyWeek.com.