DUI/DWI laws
November 2010
All 50 states and the District of Columbia have per se laws defining it as a crime to drive with a blood alcohol concentration (BAC) at or above a proscribed level, currently 0.08 percent (0.08 g alcohol per 100 ml blood).
License suspension or revocation traditionally follows conviction for alcohol-impaired driving. Under a procedure called administrative license suspension, licenses are taken before conviction when a driver fails or refuses to take a chemical test. Because administrative license suspension laws are independent of criminal procedures and are invoked right after arrest, they've been found to be more effective than traditional post-conviction sanctions. Administrative license suspension laws are in place in 41 states and the District of Columbia.
More than half of all U.S. states require DUI offenders to install ignition interlocks on their vehicles in order to drive during a license suspension and/or require interlocks for specified time periods before fully relicensing offenders. These interlock devices analyze a driver’s breath and disable the ignition if the driver has been drinking. In 13 states (Alaska, Arizona, Arkansas, Colorado, Hawaii, Illinois, Louisiana, Nebraska, New Mexico, New York, Oregon, Utah, and Washington), such a restriction is applied to all offenders, including first time offenders. California applies a similar restriction to all offenders, but only in 4 counties. An additional 9 states apply the restriction to all offenders with high BACs (usually 0.15 percent or higher) and to repeat offenders, and 6 states apply the restriction only to repeat offenders.
Laws in the remaining states do not require interlocks at all, though courts or DMVs in 18 states and the District of Columbia have the discretion to apply interlock requirements. Only 3 states (Alabama, South Dakota, and Vermont) have no interlock laws.
