What is the primary function of a tachograph in a commercial vehicle?

The tachograph primarily serves to record driving time and rest periods for commercial vehicle drivers. This device is critical for ensuring that drivers comply with regulations surrounding working hours, which are designed to enhance road safety by preventing fatigue. By accurately tracking how long a driver has been on the road and when they have taken breaks, the tachograph helps to maintain legal compliance and promote safety for both the driver and other road users.

While measuring fuel consumption, monitoring engine performance, and tracking speed limits are all important aspects of vehicle operation and management, they do not encapsulate the primary purpose of a tachograph. The focus of a tachograph is specifically on recording time-related data crucial for meeting legal standards for driving hours and ensuring necessary rest periods are taken by drivers.