Which of the following factors can affect your ability to drive safely?

The ability to drive safely is significantly influenced by factors that impair judgment and reaction times. Fatigue, for instance, can slow down a driver's response to stimuli and decrease attention to the road. Alcohol and drugs can severely impair cognitive functions, including coordination, perception, and decision-making skills, all of which are critical for safe driving. Distractions, whether from electronic devices or passengers, take a driver's focus away from the task at hand, increasing the risk of accidents.

While other factors like weather conditions, road types, the vehicle's age and make, and traffic signals do impact driving safety, the elements listed in this answer directly contribute to or detract from a driver’s ability to concentrate and react appropriately during critical driving situations.