An investigation was made about the best condition for aerial photography of cracks in motorway pavement. A stretch in Maine was used for colour, colour infrared, and black and white film. The nature and the causes of the different types of cracks (transverse, longitudinal cracks, and vertical deformations), the factors underlying the contrast of the cracks with the surrounding pavements and the conditions of the road and weather for the photography are discussed. Pavement condition itself appears to be the single most important factor on the amount of information that can be gleaned, form the photograph. Stereo photographs are definitely superior. For small objects and cracks a scale 1:2400 is recommended; for larger cracks and for general studies a scale of 1: 6000 is adequate. Eltachrome Impared Aero proved to be the best film available for intensive evaluation. Normal black and white film is adequate for studies requiring then exacting information.
Abstract