What is the purpose of a tachograph?

The primary purpose of a tachograph is to record speed, distance traveled, and driving hours. This device is essential for ensuring compliance with regulations regarding driving time and rest periods for commercial drivers, aimed at promoting safety on the roads. By accurately capturing this data, a tachograph helps enforce laws that prevent driver fatigue, thereby reducing the risk of accidents caused by tiredness and ensuring that drivers do not exceed legal limits on their working hours.

The other options serve different functions that are not related to the core purpose of a tachograph. For example, measuring tire pressure is important for vehicle maintenance and safety, but it does not relate to tracking driving behavior or compliance. Similarly, tracking fuel efficiency focuses on the vehicle's operational economy rather than the regulation of driving hours, and assisting in navigation relates to guiding drivers on routes rather than monitoring their driving patterns. Hence, the correct answer highlights the tachograph's crucial role in maintaining safety standards in commercial driving.