English: The photolog system is a sequential set of photographs, usually taken at one-hundreth mile increments and recorded on a continuous film strip, of the highway and its immediate environment. Each photograph normally provides the viewer with the date it was made, the route, milepoint, and direction of travel, but it can include other data as well. Photologging was developed more or less on the “let’s try it and find out” method by research and operations engineers. Today it is an operational tool in some 40 States. The varied uses to which photologs may be applied include evaluating the adequacy of traffic control devices, providing information for project design, identifying and evaluating high accident locations, acquiring planning inventory data and supplying data for research studies.