Most traffic accidents are caused by **drivers**. This is due to several human risk factors, such as **speeding**, **alcohol consumption**, and **distractions**. These factors are responsible for between **70 and 90 out of every 100 accidents**.

- **Distractions**: They are more common in young and older drivers, especially on weekend trips and during the day. They also occur more on roads than in cities.

- **Alcohol**: It affects the brain and vision, increasing the risk of accidents. Even small amounts can be dangerous.

In comparison, the **condition of the road** and **vehicle failures** cause fewer accidents. For example, the condition of the road is responsible for between 10 and 35 out of every 100 accidents, and vehicle failures for between 4 and 13 out of every 100. Therefore, driver behavior is the most critical factor in accident prevention.