Did you miss the part where this was warrantless and performed on the part of the NHTSA for the purported purpose of a study? You mentioned places where law enforcement agencies are capricious. Did you miss the irony?
Both threads from June 10, 2013
>>DNA collected at roadblocks [see post 73]
http://www.freerepublic.com/focus/f-chat/3029457/posts
>>Why were roadblocks in St. Clair, Bibb counties asking for blood & DNA samples this weekend? (AL)
http://www.freerepublic.com/focus/f-news/3029696/posts