This paper presents an FPGA based stereo vision system for future video tolling, which can achieve real-time processing for high resolution video streams. The key component for the system is SAD (Sum of Absolute Differences) based stereo matching. Although simple and effective, this method usually needs much computation power to satisfy real-time requirement. We propose a Hybrid-D Box-Filtering algorithm in hardware to explore disparity-level and row-level parallelism for SAD computation. This method enables processing of high resolution images with limited on-chip memory resources. The experimental results show that the system can process 46 fps (frames per second) for video of 1280*1024 resolution with a large disparity range of 256, and 400 fps for a video of 640*480 resolution with a disparity range of 128. Our results are up to 3 times better than previous work in the metric of points times disparity per second (PDS).