Checkpoint Cases
- Delaware v. Prouse: Police cannot pull over a driver solely to check their license or registration without reasonable suspicion of a violation, unless the stop occurs at a pre-established, stationary checkpoint.
- Michigan Department of State Police v. Sitz: Sobriety and license checkpoints are constitutional if they are systematic (i.e., all vehicles are stopped). However, motorists cannot be forced to answer questions or provide breath/blood samples unless officers detect signs of impairment, which then establishes the reasonable suspicion or probable cause needed for further detention.
- United States v. Martinez: Border Patrol and immigration enforcement checkpoints are legally permitted on public roads.