1. Highway Capacity Manual (1950) Bureau of public roads. U.S. Government Printing Office, Washington D.C.
2. Highway Capacity Manual (1965) Special report 87. Transportation Research Board, Washington D.C.
3. Interim Materials on Highway Capacity (1980) Circular 212. Transportation Research Board, Washington D.C.
4. Highway Capacity Manual (1985) Special report 209. Transportation Research Board, Washington D.C.
5. Highway Capacity Manual (2000) Transportation research board. 4th edn. Washington D.C.