Drive control system for vehicles

A driving control system for a vehicle includes a map information output devices for outputting a map, a vehicle position detecting device for detecting a vehicle position of a subject vehicle on the map, a vehicle speed detecting device for detecting a vehicle speed, a passable area determining device M3 for determining a passable area A on the map on the basis of the detected vehicle speed, and a passability/impassability judging device M4 for deciding that the vehicle may pass through a portion of road when a road which is in front of the vehicle position in a travelling direction is included in the passable area A on the map. The road which is in front of the vehicle positions in the travelling direction is compared with the determined passable area, and when the road is included in the passable area, it is decided that the vehicle may pass through the portion of road. Thus, it is possible to properly judge whether or not the vehicle may pass through the portion of road by a simple calculation not including a complex and poor-accuracy calculation of the radius of curvature of a road.