Q. Interstate Highway Design Standards


The Federal-Aid Highway Act of 1956 called for uniform geometric and construction standards for the Interstate System. The standards were developed by the State highway agencies, acting through the American Association of State Highway and Transportation Officials (AASHTO) and adopted by the FHWA.  The standards are included in the AASHTO publication A Policy on Design Standards -- Interstate System available from the AASHTO web site: https://bookstore.transportation.org/

Examples of design standards for the Interstate System include full control of access, design speeds of 50 to 70 miles per hour (depending on type of terrain), a minimum of two travel lanes in each direction, 12-foot lane widths, 10-foot right paved shoulder, and 4-foot left paved shoulder. Initially, the design had to be adequate to meet the traffic volumes expected in 1975. Later, the requirement was changed to a more general 20-year design period to allow for evolution of the System. http://www.fhwa.dot.gov/programadmin/interstate.cfm

  • Last Updated Dec 14, 2016
  • Views 7
  • Answered By David Martin

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