This paper studies the integration and implementation of digital image processing techniques on the roadside camera for traffic monitoring and vehicle tracking. The image processing framework developed in this study is mainly composed of five stages: (1) pre-processing, (2) foreground segmentation, (3) shadow removal, (4) tracking, and (5) traffic parameters extraction. During the pre-processing stage, the information of road geometry is obtained and the camera is calibrated. At the foreground segmentation stage and shadow removal stage, moving vehicles are segmented from the original input images. To make the system more robust, an a-β filter is used at the multi-vehicle tracking stage. Subsequently, related traffic parameters are extracted at the end of each tracking mechanism. The experimental results show that this system is capable of successfully extracting the traffic parameters, including the trajectory of the moving vehicles based on the image sequences captured by a digital camera on a free flow traffic in the daytime..