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County and Township Road Specifications

Standards for constructing a road with an Annual Average Daily Traffic (AADT) less than 100

To provide a standard for constructing a roadway to standards acceptable for maintenance by either the County or Township.

Prepare a drawing to show horizontal and vertical alignments, typical section, property and right-of-way lines, topography (including drainage ditches, culvert sizes, and direction fo flow), traffic control, erosion control measures, and location of all utilities.

Show on the drawing all of the following, if applicable:

  • North arrow
  • Bench mark
  • Dimensions fo all property lines and section lines
  • Property restrictions and zoning
  • Number of homes or lots to be served
  • All buildings, culverts, yard trees, woods, ledge rock, wetlands, rivers, lakes, etc
  • Location of all utilities, power lines, telephone cables/pedestals, etc
  • Length and width of new roadway
  • Erosion control measures
  • Traffic controls
  • Projected Annual Average Daily Traffic (AADT)

Typical Section Specifications

  • Aggregate base shall be placed on a competent subgrade. If subgrade is weak or not competent it shall be improved by excavation and backfill and/or the use of geotextiles (fabric or geogrid)
  • Clear zone of 10 feet from the edge of the driving surface or 23 feet from the centerline of the road
  • If a turn-around is required:
    • cul-de-sac shall have a minimum 60 foot radius right-of-way, 50 foot surfaced radius
    • a turning "T" shall have legs of 50 feet in either direction and perpendicular to the road centerline
  • All centerline culverts shall be CMS (Corrugated Metal Steel) no less than 18 inches in diameter
  • Entrances shall be located a minimum distance of 100 feet from the nearest road intersection and culverts shall be CMS ln less than 15 inches in diameter
  • All bridges and other structures shall meet current minimum design standards


  • All requests and plans for roadways must be submitted to the Office of the County Highway Engineer and appropriate Township Board, if applicable, for approval
  • All completed roadways will be inspected and approved for acceptance by the County Highway Engineer (or his/her designee) or the appropriate Township Board
  • According to current statutes a one year maintenance period is required after approval of the road before full acceptance is granted
  • At the discretion of the County Highway Engineer, a bond may be required to cover the estimated cost of the road construction for those roads under County jurisdiction
  • All necessary permits (NPDES, U.S. Army Corps of Engineers, DNR, Planning & Zoning, etc.) required by local, state, and federal agencies shall be obtained prior to beginning construction


  • All associated costs of planning and construction of the roadway are to be borne by the applicant
  • Waivers may be granted from these guidelines and specifications if warranted by the County Highway Engineer or appropriate Township Board

If a proposed road has the potential for a AADT greater than 100, please call the St. Louis County Public Works Department at 218-625-3830 for further assistance.

Click here for the complete St. Louis County Road Specifications