To provide a road information acquisition device capable of appropriately detecting information related to a road from a road marker, and a vehicle traveling control device and a road traffic system using it.

The road information acquisition device to be mounted on a vehicle comprises a road marker detection means 20 detecting road markers laid on a road so as to form a first road marker line and a second road marker line extending in the longitudinal direction of the road; and a road shape detection means detecting a road shape based on a positional relation between a road marker 5 belonging to the first road marker line and a road marker 7 belonging to the second road marker line which are detected by the road marker detection means 20.

COPYRIGHT: (C)2007,JPO&INPIT