Moving car information in traffic video signals contains a lot of important information on road safety. In this paper, we propose an algorithm that extracts and tracks Feature Points of cars. The information is indispensable for measuring moving car speed, counting the number of cars, monitoring distance between two cars, classifying running directions, and monitoring congestion situation. Utilizing Harris operator for detecting edges and corners, Feature Points are extracted, followed by block-matching to track the Feature Points in successive video frames. Many cars can be tracked at the same time automatically since the information is obtained by video signal processing. As an example, this paper shows car speed measurement result.