• Highway funding has proven an effective means of passing new laws.report drunk drivers sign (closeup) image by Paul Marcus from Fotolia.com
  
  Growing acknowledgment of the social costs associated with drunk driving has inspired a wave of stiffer penalties across the United States. Administrative license revocation and ignition interlock laws have become increasingly common tools for keeping drunk drivers off the road. Many of them are aimed at repeat offenders, who make up roughly for one-third of the 1.5 million impaired driving arrests logged each year and pose the biggest challenges for law enforcement.
  
  

Transportation Appropriations Act

• Originally enacted in 2000, the Transportation Appropriations Act tied federal highway construction funding to the lowering of the minimum threshold required to be found legally drunk. By July 2004, all 50 U.S. states and the District of Columbia passed laws that lowered blood alcohol concentrations (BAC) from 0.10 to 0.08 percent. From the practical standpoint, this marked the first uniform legal definition of drunken driving.
  
  

Zero Tolerance Laws

• Keeping young people from drinking is a major focus of the new legislation.teen romance image by .shock from Fotolia.com
  
  A key focus of federal intervention efforts has been to prohibit underage drivers from drinking. The first steps came in 1984, when Congress tied federal highway funding to the adoption of 21 as the legal drinking age. A similar measure followed in 1995, paving the way for so-called "zero tolerance" laws that mandated a 0.02 BAC for underage drivers caught on the roads.
  
  

License Sanctions

• Forty-one states and the District of Columbia impose some type of administrative license revocation or suspension proceedings. Such laws are among the most effective deterrents to drunk driving, since the sanctions run independently from criminal cases and can be invoked right after an arrest. Suspensions imply that the offender may eventually drive again after a set time period. The more drastic remedy of revoking licenses is generally reserved for repeat offenders.
  
  

Vehicle Impoundment

• Impounding vehicles is growing as a control method against drunk drivers.driving position image by Robert Kelly from Fotolia.com
  
  Impounding vehicles has become an increasingly popular way of dealing with multiple offenders. Twenty-seven states now impound vehicles for a variety of offenses, such as driving with expired license plates, driving without a license and driving under the influence (DUI) of alcohol or drugs. According to the National Highway Traffic Safety Administration (NHTSA), about 18 percent of all fatal crashes involve an improperly licensed driver.
  
  

Ignition Interlocks

• More than half of all states require offenders to install ignition interlocks, which analyze a driver's breath and prevent them from driving, if their blood alcohol level is over the limit. Thirteen states require the devices for all violations, including first-time offenders. Eighteen states and the District of Columbia leave the issue up to local courts or a licensing bureau. Only Alaska, South Dakota and Vermont lack any specific requirements.