Driving experts and medical researchers have tested the effects of alcohol on driving and have found that drinking at any level

• reduced the ability to judge distances, speeds, and turns
  
• reduces the ability to judge accurately one's own capabilities and limitations
  
• increases the tendency to take risks
  
• slows reflexes
  
• adds to forgetfulness of taking precautions such as using signals when turning
  
• reduces the ability to concentrate

For these reasons, only one who has had no alcohol to drink should drive. Others should always refuse rides with anyone who has had any alcohol to drink.

DWI (driving while intoxicated) and DUI (driving under the influence) are two terms for the same situation. Driving while intoxicated means that the person's blood alcohol concentration level exceeds the limit allowed by law in that state.