Adrinking driver may be able to steer or brake adequately but studies have shown

Mistakes are much more likely as the complexity of the driving situation is increased.

Explanation:

A drunken driver may perhaps, be able to steer satisfactorily but there are always chances of complications as the psychological effects of alcohol are crippling. These effects may include the development of fear, anger, and anxiety that raises the chances of making mistakes on road that may lead to hostile and impulsive behavior ending in an accident or a case of road rage. The studies have analyzed the cases of excessive hostility in drunken drivers as these are the reasons behind the prohibition of drunken driving as the alcohol impacts the mental faculties greatly and causes complexity and impulsiveness in behavior and actions.