PC*MILER Road Classifications

Interstate Highways
  • The primary function of these roads is to move high volumes of vehicular traffic over medium to long distances at high speeds
  • Can be accessed only via access ramps
Major Highways
  • Major arteries that move heavy volumes of traffic at moderate speeds
  • Can be limited access in some areas but may also offer access from local roads
  • Usually have a barrier or median that prevents movement between lanes of opposing traffic
  • Medians may have crossovers that are part of the normal traffic pattern
  • Left turns are often restricted, both off of the highway and onto the highway
  • Usually multi-lane
  • Many but not all U.S. highways are in this class
Primary Highways 
  • Move significant volumes of traffic at moderate speeds
  • Most state roads fall into this class
Secondary Roads
  • These roads move moderate volumes of traffic over short to moderate distances
  • Carry vehicles from local roads to higher class roads
Local Roads
  • Function is to provide access to homes and properties
  • A connecting road leading on or off of a main road or highway
  • Sub-local roads, which include alleys, driveways, parking lots, and service roads. (Available in Version 34 and Higher)
  • Ferry routes (boarding/exit time not included)
  • Roads that lead in or out of well sites and other facilities