HMID Standards

The High Mast Illumination Details (HMID) standard sheets contain the specifications and details for the structural, mechanical, and electrical parts of TxDOT's standard high mast lighting assemblies. It includes details for the ring, ring supports, lowering system, and other mechanical and electrical systems needed to construct a complete assembly. The HMID sheets should be included in the plans whenever high mast lighting assemblies are used on a project.