Abstract: A device for improving vehicle driving safety and comfort is disclosed. The main road sign information encountered during a journey is transmitted to the vehicle, the position of the vehicle on the driving surface is continuously monitored, and the road surface is checked for the presence of foreign matter such as mud, snow, ice, etc. A set of transmitting-receiving sensors (C1, C2) suitably arranged on the vehicle and facing the driving surface continuously observes changes in the reflective properties of the observed areas within the sensitivity range thereof. Markings defining lanes and shoulders lined with grassy, gravelly or sandy areas are sensed by the sensors (C1, C2) as soon as the vehicle approaches or drives over them. The signals from the sensors (C1, C2) are processed by an electronic unit (1) controlling an on-board signalling system (2) linked to an alarm system (3) for warning the driver of road hazards and possible unsafe driving (straying off-course, speeding, etc.).