Federal regulations require after-market safety devices for added protection of heavy truck cab occupants. One major safety device required under the Federal Motor Carrier Safety Regulations (FMCSR) is a “header board” otherwise known as a “headache rack” or “cab guard.” The purpose of a cab guard is to protect the cab and occupants in the event of a load shift. A header board can be placed directly on a heavy truck behind the cab, attached to the frame rails, or can be attached to the trailer being pulled by the heavy truck. When attached to the trailer, the header board is commonly referred to as the “bulkhead.” FMCSR requires only one header board, either on the tractor or trailer. There is no requirement for a header board on a closed box trailer. The header board is part of the FMCSR’s cargo securement system, which includes trailer anchor points and cargo tie down materials such as cables or straps. Cargo securement is generally left to the discretion of heavy truck operators, with guidance from the FMCSR.
The FMCSR provides performance criteria, not design criteria, for cab guards. §393.114 governs the performance requirements of a cab guard (§393.106 prior to 2004 revisions). Performance requirements under §393.114 require that a cab guard be able to resist a static load equal to 50% of the weight of the cargo being transported uniformly distributed over the entire surface of the cab guard. For certain taller cab guards, the requirement is 40% of the weight of the cargo being transported. §393.114 also has a penetration requirement that no article being transported can penetrate the cab guard when the vehicle decelerates at a rate of 20-feet per second, which is approximately .5 g’s.
Cab guard manufacturers have taken the performance requirements of § 393.114 and translated them into a loose design protocol. In most instances, cab guard manufacturers have developed uniform weight distribution tests or static tests to determine if their cab guards can meet the performance requirements of §393.114. Our experience has shown that typically cab guard manufacturers statically load a welded aluminum cab guard that has been designed to fail at 20,000-25,000 pounds. According to the language of §393.114, such a guard would meet the performance requirement for cargo weighing 40,000-50,000 pounds. However, cab guard manufacturers are placing weight limitation stickers on their products that are somewhat misleading. In most instances warning stickers indicate that cab guards have been tested to “comply” with FMCSR requirements for suitable loads of 40,000-50,000 pounds. The manufacturers never inform operators that the cab guards have actually failed at static loads of 20,000-25,000 pounds. Thus, the warning labels give the impression that the guard will actually resist a load of 40,000-50,000 pounds.
More importantly, our experience with the cab guard industry is that they have never tested their products dynamically to determine how the product will perform under real-world accident conditions. Typically, cab guard manufacturers claim that as long as they comply with the performance criteria of §393.114, they have done all that is required from a product performance standpoint. In other words, they say, we complied with Federal Standards so our product is reasonably safe.
Interestingly, the FMCSR applies only to heavy truck operators, not cab guard manufacturers. In some instances, cab guard manufacturers cannot show that any product engineering ever occurred. In some cases, manufacturers have taken the position that their cab guards are not designed to protect the cab during accidents but rather during normal braking. However, the products are marketed as safety devices to protect drivers and occupants during the event of load shifts. Cab guard manufacturers generally admit that their product is intended to protect occupants from shifting cargo and admit that they have not restricted use to only non-accident circumstances.
Most cab guards are made of heat-treated aluminum. This material allows for the production of a light weight product that is relatively easy to maintain. However, welding heat-treated aluminum generally reduces the strength of the aluminum by one third. Welded aluminum is also subject to structural fatigue due to cyclical loading during truck operation. This structure fatigue also erodes the strength of the cab guard. Finally, welded aluminum will not bend or stretch under loads like steel. Therefore, when welded aluminum reaches its maximum load, it typically fractures and catophysically fails. A steel cab guard will not fail in such a fashion and typically provides better protection to occupants, even past its predicted loading capacity. If a manufacturer is going to market a safety device, it should have appropriate engineering and design. Current aluminum cab guards generally miss their mark for safety. If you need more information on this subject, contact Ben Baker, a lawyer in our firm who handles this litigation, at 800-898-2034 or by email at Ben.Baker@beasleyallen.com.