In 1997, The TRB and the National Research Council published the proceedings from their conference "Decennial Census Data for Transportation Planning: Case Studies and Strategies for 2000." I've been struggling to get a sense of the history and measurement issues for the CTPP and Census in general. It's a gem. Volume I provides an overview and summary, while Volume 2: Case Studies goes into some of the meaty, detailed research and applications of the data (Will need a really big cup of coffee and a quiet place for that one). Just thought I'd pass this along... Liz Hartmann Research Analysis Specialist MnDOT