On May 20 INDOT released Design Memorandum No. 16-21 Technical Advisory: Semi-Smooth Pipe Interior Designation. All current and archived design memos can be found on the Department website at http://www.in.gov/dot/div/contracts/standards/memos/memos.html. Direct questions to Elizabeth Phillips, INDOT Standards and Policy Division of Bridges at (317) 232-6775.