- 0.02 percent. Some decrease in the ability to track moving objects and to multitask, a key skill when driving.
- 0.05 percent. The ability to coordinate movements, especially in emergency situations that require quick thinking, goes down. Decreased ability to steer a vehicle properly.
- 0.08 percent. Coordination, short-term memory, perception, and the ability to process things the driver sees, hears, or feels are all impaired. This is currently the “legal limit†for BAC in all fifty U.S. states.
- 0.10 to 0.15 percent. The ability to keep the car on the road, brake properly in response to traffic signals, turns, or things in the road ahead, and the ability to process information are all significantly impaired.
DUI/DWI
New Hampshire DUI: How Does My Driving Ability Decrease as My BAC Increases?
Laws prohibiting driving under the influence of alcohol (DUI) in New Hampshire and other states are based on research indicating that a person’s ability to drive a motor vehicle safely decreases as their blood alcohol concentration (BAC) increases. The BAC limit in New Hampshire is 0.08 percent, but even if a driver’s BAC is lower than this, he or she may be arrested on suspicion of driving while intoxicated, or when one’s ability is impaired (DWI).
How does driving ability decrease as BAC increases? The U.S. Centers for Disease Control and Prevention (CDC) offers an overview:
