Driver error is the most common reason for accidents involving trailers. Motorists tend to forget that with a trailer, they are operating a vehicle combination that is longer, heavier and sometimes wider and/or taller than what they normally drive.
Adding a trailer requires you adjust your driving habits to accommodate the additional weight and length.
A second reason for trailer accidents is the driver failing to adjust speed and driving habits to weather and road conditions. Again, the combined vehicles are heavier and longer and in poor driving conditions, stopping time is greater. (See Special towing considerations.)
Trailer sway, due to improper loading, is the third most common reason for accidents. Make sure your cargo is properly distributed in the trailer with the most weight over the trailer axles.
Failure to perform routine maintenance is the fourth reason. Check the
lug nuts as well as tire pressure before each trip. If the trailer has
been idle for several months, grease the bearings, as condensation can
build up in the bearings causing corrosion. Also, make sure the coupler
is adequately lubricated.