Transportation/traffic engineering studies tend to fall into four basic categories (Roess et al., 2004): (1) physical inventories, such as roadway characteristics and conditions, control devices, and parking spaces; (2) population characteristics, such as road-user and vehicle-population data; (3) measurement of operational parameters, such as volume, speed, and density; and (4) special studies such as accident and parking studies, and trip generation/traffic impact studies. The review in this section is limited to the following four principal classes of traffic engineering studies: volume studies, speed studies, accident studies, and traffic impact studies.

Additional information on designing and conducting traffic engineering studies can be found in the ITE Manual of Transportation Engineering Studies (Robertson, 2000).