What constitutes coercion when a search warrant is used to search a motorist's car?

constitutes coercion; the government cannot be said to have established that the defendant freely and voluntarily consent[ed] to the search when to do otherwise would have meant foregoing the right to travel' "]; see Missouri v. McNeely (2013) 569 U.S. , , 133 S.Ct. 1552, 1565, 185 L.Ed.2d 696 (McNeely ) ["the fact that people are 'accorded less privacy in ... automobiles because of th[e] compelling government need for regulation,' does not diminish a motorist's privacy interest in preventing an agent of the government from piercing his skin"].)