"Zero Tolerance" Blood Alcohol Concentration (BAC) Level
Zero tolerance laws apply to drivers under the legal drinking age (21). All states have a zero tolerance law. The law carries strict penalties for persons under 21 that are found driving with a BAC above 0.0; that is, there is “zero tolerance” for violators. Some states allow that .01 and .02 are negligible amounts and are not illegal. 

"Implied Consent" Laws
An implied consent law means that if suspected of DUI, a driver must agree to take a chemical test (breath, blood, or urine). The penalties, simply for refusing to submit to the test, are quite harsh. Typically, they include the suspension of the driver’s license for six months to a year.

Administrative License Suspension/Revocation
These are the minimum mandatory penalties for a legally intoxicated driver (or a driver who refuses to take a chemical test). It is not related to criminal penalties for a conviction, but rather is a sanction imposed by the state Department of Motor Vehicles (DMV) or some other specified agency. Sanctions are more severe for repeat offenders. Generally, a repeat offense means that two offenses occur within any five year period. 

Mandatory Alcohol Education and Assessment/Treatment
Mandatory Alcohol Education and Assessment/Treatment programs may include requiring attendance of DUI prevention and awareness programs or determining if the individual has an alcohol dependency problem. Often, this type of program is used as a required portion of probation or a suspended sentence. Not all states utilize Mandatory Alcohol Education and Assessment/Treatment programs. 

Ignition Interlock
This is a device, which can be required by some states, that does not allow a vehicle to be operated by an intoxicated driver. Similar to a Breathalyzer, it measures the BAC of the driver. If the result is higher than .02, the vehicle cannot be operated. Furthermore, the DUI offender must pay all costs associated with the device, including rental, installation, and maintenance.