Originally Posted by
crhilton
This is all if they don't have reasonable suspicion that you're drunk right? As I remember when I lived in Iowa they could require you to come take a blood test at a hospital, which people would opt for because it gave them about an hour to sober up and the cop had to be serious to spend his time doing that.
There may well be some variation, but I believe they require a warrant to compel a blood alcohol test or breathalyzer . Like any other application of the 4th amendment, a court issued warrant meats the due process requirement.