Often Result From Driver Misuse Or Neglected Maintenance
Vehicle-related factors were cited as a cause of approximately 4.2 percent of fatal truck crashes in 2010. Along with other factors, including defective tires and defective lights, one of the key vehicle-related factors was unsafe brakes, according to NHTSA’s Fatality Analysis Reporting System (FARS).
Because they weigh much more than passenger vehicles, trucks have a much longer stopping distance. The brakes on tractor-trailers and many other heavy trucks work differently from the brakes on a standard passenger vehicle. Tractor-trailers and other large vehicles are generally equipped with compressed air brake systems, while cars and light trucks use hydraulic brakes.
Compressed air brake systems have separate parts, including control pedals; parking brakes; service brakes; an air compressor driven by the engine; and a compressed air storage tank. When a truck driver steps on the brake pedal, it creates pressure that moves air to the brake chamber. This causes the brakes to reduce the rotation speed of the wheel. While this is a more effective means of stopping large vehicles, the brake systems are also prone to failure without proper use or maintenance. Unfortunately, the failure of truck brakes can be a significant contributing factor in large truck and tractor-trailer accidents.
Driver Responsibility for Truck Brake Failure
Most large trucks and tractor-trailers not only have an air brake system but also have a secondary braking system to prevent devastating accidents that occur when a truck cannot slow and stop properly. Despite the backup system and despite the fact that air brakes are generally considered to be a very reliable braking system, vehicle accidents involving a truck’s braking problems do happen.
In many cases, when a brake failure occurs, it is because the driver was operating the vehicle in a way that put too much stress on the brakes or because the driver didn’t use the brake system correctly.
Typically, even when there are deficiencies in the brake system of a tractor-trailer, the brakes still provide some friction that will cause the vehicle to slow and stop. However, problems with the brakes can cause the brakes to be less effective and to perform at less than full capacity. This means that when any problem, even a small one, develops in the braking system, a driver can exacerbate that problem and cause an accident by putting stress on the brakes in an emergency situation.
Because air brakes require a great deal of maintenance, it is not uncommon for some deficiencies to exist. Drivers who operate tractor-trailers should understand that air brakes, and even secondary systems, aren’t always going to work flawlessly at 100 percent braking capacity. They should realize that when they put stress on the brakes by stopping short or riding the brakes on a downhill grade, this greatly increases their chance of an accident. They should avoid following too closely, driving too quickly or otherwise engaging in behaviors that might cause them to need to slam on the brakes.
Air brakes are also prone to brake sensitivity, especially when drivers use the brakes too hard. Brake sensitivity is especially a problem with inexperienced drivers who apply too much pressure, but is also especially likely to cause issues when it is raining or snowing. Jackknifing, which is defined as the vehicle essentially folding together or as a trailer rotating so it is up next to the tractor, can be caused by applying the brakes suddenly and quickly. A driver who brakes and swerves simultaneously could also cause the truck to jackknife. Drivers should be trained on proper use of air brakes and should always be sure to brake correctly when operating a tractor-trailer.
Maintenance Problems and Truck Brake Failure
A great number of truck accidents blamed on “brake failure” are really accidents caused by insufficient maintenance procedures.
While bad driving is a possible cause of braking accidents, trucking companies and drivers may be responsible in another way for causing accidents that result from bad brakes. If trucking companies and drivers fail to maintain their brakes properly, this can result in the braking system’s failing to perform correctly. In fact, neglected maintenance and failure to comply with federal and state maintenance requirements are some of the most common causes of accidents related to faulty brakes in trucks.
A variety of different maintenance failures can result in problems with an air brake system. Some examples include:
- Torque imbalance-- If a brake system has mismatched mechanical components, components that don’t work properly or components that aren’t adjusted correctly, this can cause the brakes on some wheels to work harder than others and to make them more prone to locking up. Individual brakes are usually affected when torque imbalance occurs, and jackknifing is one likely result. Trailer swing-out is another common result and occurs when the trailer’s axles brake with greater force than the tractor and the trailer begins to swing outward.
- Pneumatic imbalance-- Pneumatic imbalance occurs when the air pressure is not equal on all wheel ends. Like with torque imbalance, some brakes will work harder than others and be more likely to lock up. However, when pneumatic imbalance is the problem, typically an entire axle or set of axles will be affected rather than individual wheels. Jackknifing and trailer swing-outs are again common with brake imbalance.
- Water in the air brake system --Because air brakes used condensed air, water is an inevitable byproduct. Unfortunately, water in air brake lines can cause issues, especially when the weather is cold and ice forms and blocks air from getting through. When this occurs, the wheels may lock up on the vehicle. Modern braking systems typically have automatic drain valves installed in air tanks to prevent water from getting into the air brake system, but this is still a potential problem in older vehicles or if the valves don’t work perfectly.
- Worn rubber seals on air couplers-- This can cause air to escape, resulting in air being unable to reach the braking system and the wheels’ locking up as a result.
All of these problems can potentially be prevented by performing routine inspections of the brakes and by ensuring that brake maintenance is a top priority. Of course, not every brake failure accident is caused by improper maintenance. For example, improper brake design or manufacturing defects could also be to blame.
Proper Brake Maintenance Procedures Can Prevent Accidents
Many of the potential problems with the brakes on tractor-trailers can be identified by making sure the braking system works properly before a trip begins. According to Title 49 Part 392.6 of the Code of Federal Regulations, truck drivers must perform a basic inspection of their vehicles daily and note any problems in a log. When soft or grabby brakes or other problems are noted, the issues must be corrected before the truck is driven again.
A thorough inspection of the braking system should include checking the brake linings for wear or imbalance, as well as checking for worn seals and water in the air brake system. The inspection should also involve verifying the air pressure buildup rate, confirming the cut-out and cut-in pressure for the air compressor and ensuring that the minimum operating pressure of the air brake system does not drop below 100 psi for trucks.
Why Does Brake Maintenance and Driver Behavior Matter?
Truck drivers and trucking companies are the best line of defense against serious trucking accidents caused by brake failures. If a truck accident occurs, it is important to identify whether there was a failure in either maintenance or vehicle operation.
If a truck accident was caused solely by a design or manufacturing failure in the truck or its braking system, then the manufacturer could be held responsible in a product liability lawsuit. However, if a truck driver failed to operate the vehicle safely or failed to perform routine brake inspections, then the truck driver could be held legally liable and made to compensate the victims of the truck accident. The trucking company could also be held responsible for a driver’s failure because it employs the driver, or the trucking company could be held responsible for an accident that occurs due to insufficient or improper maintenance of trucks in its fleet.Truck accidents, especially those that involve brake failures, raise extremely complex legal issues due to the fact that an apparent problem with the brakes often results in the driver and/or trucking company’s bearing some responsibility for the accident. It is always advisable to seek legal assistance in truck accident cases.