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Ancillary Structures

An ancillary structure supporting directional freeway signs over a freeway.
Department of Transportation

Ancillary Structures

MDOT's Ancillary Structures Unit implements the department's asset management program for ancillary structures per the Michigan Ancillary Structures Manual (MiASM). They perform comprehensive asset management of ancillary structures, serve as MDOT's ancillary structures expert, and provide data to region staff regarding ancillary structure inventory, inspection, and maintenance issues. They also perform structural design technical reviews of detailed shop drawings and field construction related documents required to be submitted for review and approval.

Ancillary Structures

  • Sign Cantilever
  • Communication Tower
  • Dynamic Message Sign (DMS) Support Structure
  • Environmental Sensor Station (ESS) Lattice Tower
  • Lighting Tower
  • Noise Barrier Wall
  • Retaining Wall
  • Spun Concrete Pole
  • Steel Strain Pole
  • Sign Truss
  • Wood Pole
  • Culverts Less Than 10 Feet
  • Frangible Lights
  • Non-Frangible Lights
  • Embedded Poles
  • Mast Arms


Michigan Ancillary Structure Inspection Manual (MiASIM)

MiASIM Appendix A

MiASIM Appendix B


Michelle O'Neill, Ancillary Structures Engineer

Vacant, Statewide Ancillary Structures Development Specialist

Sue Taylor, Sign Cantilever/Truss Specialist

Tom Zurburg, Noise Wall Specialist

Michelle Harris, Ancillary Structures Transportation Technician