The implied consent DUI law says that you must consent to a chemical test or risk losing your license if an officer suspects you of driving under the influence.
Think of it as a deal you made with the State that issued your drivers license, and a deal you make with any state the moment you get behind a wheel or mount a motorcycle. You agreed that if an officer suspects you of driving under the influence of alcohol (or sometimes drugs), you have given your consent for them to take a chemical test from you to determine you blood alcohol level.
As the name suggests, the consent is implied and not explicit. This means that you can always refuse to cooperate and take the test by withdrawing your consent. The implied consent statutes that are part of state DUI law spell out the penalties and drawbacks of withdrawing your consent and refusing to participate in chemical testing.
In a nutshell, if you withdraw your consent you will lose your license, typically for a one year period for a first refusal. If you do, then, depending on the state, the officer may still have an opportunity to get a search warrant from a judge to take your blood, thereby getting around your non-consent.
If you refuse a chemical test, or if the officer alleges that you did because either the machine didn't work or you weren't being cooperative, you typically have a right to request a hearing to ask an administrative law judge at the DMV to review the facts of the case and reverse the license suspension.
Keep in mind that typically you must request a hearing within a very short period of time from your arrest, or you will lose your right to a hearing and therefore your license. Check individual state laws for the specific requirements of the DUI implied consent statute that applies to your case. Make sure that you contact a local DUI lawyer before time to request a hearing expires.