Estimation of traffic load effects on Forth Road Bridge using camera measurements

This paper explores the possibility of using a camera and image analysis to extract congested traffic data. A video system was installed on the Forth Road Bridge. The system captured traffic video data at a rate of 1 frame per second for approximately five months. Simple image processing methods, e.g. adaptive thresholding and morphological reconstruction, are used to automatically analyse the images extracted from the videos. The body shapes of the vehicles are accurately extracted. Identified vehicles are framed within rectangles and the rectangle's dimensions are used to approximate the length of the vehicles. The study confirms that the image data can be used efficiently to measure the lengths of the vehicles. The vehicle lengths can be ultimately used for the estimation of site specific characteristic maximum traffic load effects.