Design Memo 17-26 Subgrade Treatment describes the addition of Subgrade Treatment Type IVA to the Standard Specifications.
Design Memo 17-27 ta Bridge Length Culverts clarifies exceptions to the Level One Controlling Criteria for bridge length culverts.
Design Memo 17-28 ta Plant Growth Layer includes guidance on the necessary prerequisites for use of RSP 629-R-630, Plant Growth Layer.