There is provided a traffic information providing system comprising: a road-interior communications unit embedded in a road for providing a vehicle travelling on the road with location information from which a position of the vehicle is estimated; and a road-periphery communications unit installed in a vicinity of the road for estimating a traffic condition by communicating with the vehicle information on the estimation of a traffic condition and providing the vehicle with the estimated traffic condition, wherein the road-periphery communications unit is placed in a road section and communicates with another road-periphery communications unit installed in another road section.