Many different factors contribute to the more than two million crashes that occur each year on America’s roads and highways. According to the National Highway Traffic Safety Administration (NHTSA), these crashes involved around four million cars and drivers and nearly two million passengers. While causation data is not collected and analyzed for each crash that occurs, our Indianapolis car accident lawyer adds, that NHTSA conducted a causation study over a two-year period and the information they gathered had been invaluable in understanding why crashes occur and what can be done to prevent them.
Results of the Causation Study
In an overwhelming number of crashes, the critical event leading to the cause was determined to be driver error, such as distracted driving, speeding, or driving while intoxicated. A critical event is the last event in the crash causal chain. In other words, there could be several contributing factors to a 
crash, but the final significant event in 94 percent of accidents was determined to be something the driver did or did not do.
The study found the second-leading cause of crashes to be related to a malfunction in a component of the vehicle. Coming in at only two percent, but accounting for over 44,000 crashes a year, failure of mechanical parts does have an impact on driver and passenger safety.
Causes of Crashes Attributed to Vehicles in Indiana
Because NHTSA’s study looks at the last critical event in the causal chain, it is likely that vehicle malfunction contributes to more than two percent of accidents.
However, the study found that it was more often the driver's response to a malfunction than the malfunction itself that was the primary cause. For example, if a driver reacts to a tire blowout by swerving into oncoming traffic, the primary cause of the crash would be driver action, not mechanical failure. NHTSA identified defects with the following systems as contributing to a significant number of crashes each year:
- Tires. Tires that are worn, underinflated, unbalanced or improperly weighted, incorrectly mounted or installed, or wrong for the vehicle can all contribute to the driver losing control of the vehicle.
- Brakes. Good brakes are obviously essential to the safe operation of a vehicle. When a brake’s pads, lines, cylinders, or pedals are in poor condition, braking could become difficult or impossible, leading to an unavoidable crash.
- Steering. When there is a problem with the power steering pump, hydraulic lines, tie rods, or any other part of the steering and suspension system, a driver may not be able to avoid an accident.
- Engine. A seized engine or malfunctioning transmission could cause a driver to lose control of the car or force the car to stop suddenly, creating a hazard for others.
Other mechanical failures not identified in the NHTSA study that can be a contributing factor in a crash, include the following:
- Airbags. A defective airbag could deploy randomly, injuring the driver and causing an accident.
- Windshield wipers. When defective wipers fail to adequately clear the windshield during heavy rain or snow, the driver is left blind to what is ahead of him and could crash into something.
- Gas tanks. Poorly designed or poorly placed fuel tanks can put a vehicle at risk for a fire with the smallest impact. When a vehicle catches fire after a fender bender, the fault is likely with the fuel tank.
- Ignition. As seen in the recent GM case, a faulty ignition switch could cause a car to suddenly shut the engine off during driving, clearly a dangerous event.
- Crash avoidance systems. Tech-savvy drivers come to rely on these systems to help them avoid obstacles. When a sensor malfunctions and the driver is not notified of the failure, he could back into another car or change lanes into the path of another vehicle.
