Most states have laws on the books that require you to agree to a sobriety check as a precondition of getting a driver&#x27;s license. I think that also includes agreeing to a blood-draw if you get booked for DWI. Refusing is grounds for revocation of your license.<p>Now all that aside, this is quite a stretch ... If the 5th amendment protects you from disclosing a password under a court order, there&#x27;s no reason you should have to unlock your phone just because a police officer asks you too. Come to think of it, pretty sure that applies that unlocking your trunk either unless the officer has a warrant.