What is the implied consent law?

What refusal normally costs

• An automatic licence suspension, commonly 6 to 18 months for a first refusal and longer for repeats — often longer than the suspension for failing the test.
• Admissibility of the refusal as evidence at trial in most states, where prosecutors argue it shows consciousness of guilt.
• In some states, an enhanced sentence on conviction, and mandatory ignition interlock on reinstatement.

Roadside tests are a different thing

Implied consent covers the evidentiary test after arrest. Preliminary roadside breath tests and field sobriety exercises are, in most states, voluntary for adult drivers — though refusing them can itself contribute to probable cause. Commercial drivers and drivers under 21 face stricter rules almost everywhere.

The blood-test limit

In Birchfield v. North Dakota (2016) the Supreme Court held that a breath test may be required incident to a lawful DUI arrest, but a blood draw generally requires a warrant or valid consent, and a state may not make refusal of a warrantless blood test a crime. Mitchell v. Wisconsin (2019) added that an unconscious driver will usually fall within the exigent-circumstances exception.

The deadline nobody tells you about

The licence suspension is an administrative action that runs on its own track. Most states give only 7 to 30 days from the arrest to request a hearing, and missing that window forfeits the licence challenge even if the criminal case is later dismissed.