Tuesday, August 31, 2010

Trailer Sway

Trailer sway, commonly known as “fishtailing,” in the side-to-side movement of an RV or Cargo trailer as an automobile is pulling it. This movement can easily cause the tow vehicle to become unstable and roll over causing a roadway tragedy.
Each year many American families hit the roads to go camping. Nationwide, there may be as many as 3 million RV enthusiasts, including renters, and by 2010 the number of RV-owning households is estimated to rise to nearly 8 million. These figures do not include cargo trailers for rent such as “U Hauls.” The phenomenon of trailer sway can occur when the tow vehicle/trailer combination is being passed by a tractor-trailer, hit by a sudden wind gust, or when the driver is forced to make an evasive maneuver. One of the biggest problems facing RV users is that no one actually advises them about the hazards of trailer sway or how they should react if they encounter it. Despite the RV industry’s knowledge about the dangers of trailer sway, the industry has done virtually nothing to warn consumers or to take measures to protect consumers from the danger. This is partly due to the fact that RV manufacturers are not actually required to test the real world performance of their products, and therefore do not.
In 1964, the federal government commissioned a study of single vehicle accidents on Route 66 and concluded that vehicles pulling trailers were substantially more likely to be involved in an accident. A more recent analysis of federal crash data shows that vehicles pulling trailers are more than twice as likely to experience a loss of control and crash than vehicles that are not pulling trailers. Because vehicles towing trailers usually have more occupants, more people are exposed to the dangers of trailer sway and the risk of injury and death. Each year, about 283 people are serious injured and 121 are killed.
Although the industry does not promote them, there are fairly inexpensive methods to prevent trailer sway. The two most common are (1) hitch ball systems where the trailer’s pivot point is at the hitch and (2) axle-type systems that put the trailer’s pivot point closer to the rear axle of the tow vehicle.
One type of sway control system is the hitch ball system. This system uses a “friction sway control device.” As the name implies, a friction sway control device relies on friction to resist the pivotal movement of the trailer on the hitch ball. These devices have been on the market for over 40 years with little change in design. Moreover, these devices are cheap, easy for dealers to sell, and simple to install and detach.
The second type of sway control system is the superior axle-type system. In contrast to the hitch ball systems, axle systems are designed to move the pivot point from the hitch ball forward, closer to the rear axle of the tow vehicle. By moving the pivot point closer to the rear axle, an axle-type system dramatically reduces the side forces the trailer exerts on the tow vehicle. The practical effect of the axle system is twofold: First, because the forces on the two vehicles are much lower, trailer sway is much less likely to ever become a problem. Second, once the trailer does being to sway, an axle system has a much higher “damping” effect, w hereby the sway is quickly eliminated. For almost all commonly used RV configurations, the axle-type system is dramatically more effective than the hitch ball system in preventing trailer sway related accidents.
As the number of RV sales increase year by year, there are even larger numbers of consumers pulling large trailers who are unaware of the lurking danger of trailer sway. Unless manufacturers begin to warn consumers about these risks, and provide information about the effectiveness – or relative ineffectiveness – of anti-sway devices, the number of trailer sway related accidents are certain to increase each year.

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