Alcohol is a dangerous substance when taken irresponsibly because it disrupts our concentration, coordination, observation, discipline and patience. Driving needs all of the skills mentioned and then some.
The legal limit of BAC (blood alcohol concentration) is 0.08 for most states, which approximately means two drinks for a 120-pound person.
At 0.02 BAC, the body experiences a slight reduction in visual functions, a decline in their abilities to track a moving object and a drop in the ability to multi-task. These changes, however subtle, are very crucial in emergency situations especially when behind the wheel of a vehicle. It can cause a distortion in the driver’s reaction time and decision making.
At 0.05 BAC level, drinkers might experience exaggerated behaviour, loss of minute-muscle control such their eyes being not able to focus quickly, have weakened judgement, poorer alertness and a release of inhibition. If someone with this level of BAC gets behind the wheel, he will have a reduction in coordination, diminished ability to track moving objects like the cars around him, a difficulty in steering the car and a lowered response-time to emergency situations.
At 0.08 BAC, studies show that the driver at the wheel would now have poor muscle coordination which leads to a loss of balance, slurred speech, poor vision, slowed reaction time and lowered hearing. This driver will find it very difficult to detect danger and exhibit poor judgement, reasoning ability, memory and self-control.