Implied consent laws say that by driving on a public road, you have consented to provide a breath, blood, or urine sample if a police officer has reasonable suspicion of impairment. Refusing the test triggers automatic license consequences separate from the criminal case.
In Missouri, refusing chemical testing results in a 1-year license revocation under § 577.041. In Illinois, refusal triggers a Statutory Summary Suspension (1 year for a first refusal, longer for subsequent).
Implied consent applies only to chemical testing after arrest, not to roadside field sobriety tests. Field sobriety tests can typically be declined without separate civil penalty (though refusal may give the officer additional grounds for arrest).