Which of the following is a cause of road crashes?

Not scanning the road for pedestrians significantly contributes to road crashes because it directly affects a driver's awareness of their surroundings. Pedestrians can unexpectedly enter the roadway, and if drivers are not actively looking for them, they may not react in time to avoid a collision. This lack of vigilance, particularly in high pedestrian areas, increases the risk of accidents.

In contrast, using cruise control can help maintain a steady speed on highways, driving with headlights on improves visibility, especially in low-light conditions, and maintaining lane discipline ensures that the vehicle stays within its designated area, all of which are essential practices for safe driving and do not inherently lead to road crashes.