Most car navigation systems estimate the car position from dead reckoning and the Global Positioning System (GPS), However, because of the unknown GPS noise, the estimated position has an undesirable error. To solve this problem, a map-matching method is introduced, which uses a digital road map to correct the position error. In this paper, a novel adaptive-fuzzy-network-based C-measure algorithm is proposed, which can find the exact road on which a car moves. The C-measure algorithm is easy to calculate, and calculation time does not increase exponentially with the increase of junctions. For the experiments, a car navigation system is implemented,with a small number of sensors. The real road experiments demonstrate the effectiveness and applicability of the proposed algorithm and the developed car navigation system.