Which factor may contribute to traffic collisions?

Overconfidence is a significant factor that can contribute to traffic collisions. When drivers exhibit overconfidence, they may underestimate the risks associated with their driving abilities or the conditions of the road. This often leads to reckless behavior, such as speeding or making unsafe maneuvers, because they believe they can handle situations that may actually be dangerous.

In contrast, careful planning can help mitigate risks by preparing drivers for potential hazards and encouraging safe driving practices. The speed of light, while an interesting scientific principle, has no direct relevance to traffic safety. Significant mileage in itself doesn't directly lead to collisions unless it is associated with factors like fatigue or poor driving behavior. Thus, overconfidence represents a behavioral risk that can directly influence decision-making and increase the likelihood of accidents on the road.