The document discusses using machine learning for intelligent transportation systems based on vehicle perception. It provides an overview of how machine learning has been increasingly used for tasks like vehicle detection, counting, classification, identification and speed detection. Specifically, it describes approaches like background subtraction, optical flow and deep learning models that have been applied to problems in traffic monitoring, management and road safety. The document also reviews common computer vision algorithms in OpenCV that can be utilized for these tasks and considers factors like speed, accuracy and complexity in choosing the appropriate methods.