What accounts for about 90% of crashes?

• A. Human error
• B. Mechanical failure
• C. Weather
• D. Road design

Answer: (A)

Human error is the main factor behind the vast majority of crashes. Most crashes happen because a driver makes a mistake or poor decision—things like not keeping a safe following distance, speeding, distracted or impaired driving, or misjudging a gap in traffic. These human factors are responsible for about 90% of crashes, which is why improving driver behavior and decision-making has the biggest impact on preventing crashes.

Mechanical problems, adverse weather, and road design can contribute to crashes, but they’re less often the primary cause. When they do play a role, they typically interact with driver actions (for example, slippery roads requiring longer stopping distances or a vehicle malfunction that reduces control), but the initiating factor is usually something a driver does or fails to do. Understanding this helps officers focus on preventive driving habits—scanning, maintaining safe speeds and distances, staying sober and alert, and anticipating others’ actions—to reduce crash risk.