**Traffic accidents** are a significant problem and can be classified according to their main causes: **human factors**, **road conditions**, and **vehicle failures**.

- **Human factors**: These are the most common cause of traffic accidents, accounting for between **70 and 90 out of every 100 accidents**. These factors include behaviors such as speeding, alcohol consumption, and distractions while driving. Most of these accidents can be avoided if drivers adopt responsible behaviors, such as not consuming alcohol before driving and keeping their attention on the road.

- **Road conditions**: This factor is responsible for between **10 and 35 out of every 100 accidents**. Adverse conditions, such as wet roads, can increase the risk of losing control of the vehicle, especially on curves.

- **Vehicle failure**: Mechanical problems, such as brake failures or tire blowouts, cause between **4 and 13 out of every 100 accidents**. Checking the vehicle's condition before a trip can help prevent these incidents.

In summary, **human factors** are the most frequent cause of traffic accidents, making the correct answer that between **70 and 90 out of every 100 accidents** are caused by these factors.