Abstract: This invention is of a traffic survey system in which an aerial photo survey transparency is first made of a significant survey area, for example, two kilometers square. The transparency is then optically scanned to check the position and size of vehicles on roadways in the area. By computer control comparison with a reference transparency wherein areas other than roadways are made opaque and roadways are made clear, scanning may be directed solely to roadway regions. Vehicle size analysis is accomplished by means of discrete holographic filters corresponding to selected size vehicles.