actually, NHTSA (national highway traffic safety administration) and several studies have shown that REASONABLE doses of stimulants, to include cocaine, IMPROVE driving.
as opposed to drugs like alcohol.
the military has provided amphetamines for pilots and special forces personnel in certain circumstances
this is not advocacy for cocaine. cocaine is illegal (unless used by prescription - such as in nasal surgery), but it is a fact that cocaine can improve driving.
of course, like many drugs there is a u shaped response curve, and high doses of cocaine would diminish driving skill