Abstract
A method is discussed of estimating the volume of OD traffic using an image recognition system (AVI) that recognizes number plates. The AVI system can estimate an inferred expected value and a dispersion value that shows its reliability calculated from the following measured parameters: number plates collated between AVIs, index of AVI recognition performance, and number of vehicles counted by a vehicle sensor connected to the AVI. The method of estimation proposes two ways: a simple one estimating traffic volume with regular traffic flow, and another one estimating traffic volume whose flow varies with time. The validity of these estimation methods has been assessed by simulations.