While DUI/DWI roadblocks/checkpoints are technically legal, police must follow certain requirements in order for any DUI/DWI arrests to be lawful, including placing roadblocks in locations that are designed to serve public safety (i.e. in locations with high rates of DUI/DWI) and selecting vehicles to submit to investigation in a fair, objective manner, such as by pulling over every fourth vehicle that passes through the roadblock -- officers may not intentionally select particular vehicles to pull over in the roadblock. If the legal requirements for a DUI/DWI roadblock were not followed, any stops and arrests from the roadblock may be deemed unconstitutional.