And as you acknowledge, planning ahead and including bike facilities can make the job easier... so why the heck are so many road projects done that end up "adding" bike lanes/paths as a last minute "bastard step child." One such project I can think of was the conversion of a farm highway to a limited access freeway... this changed the dynamics of the road, and it was realized that a bike path would be required to allow cyclists to go along the same route they used for years. But the bike path required it's own environmental impact study, which delayed the path and the delay drove up the costs. Had the path been planned with the road... the EIS could have covered both as well as allowed using the same build crew and equipment to reduce costs. This happens all too often.