Dr. Ronald Pies wrote in the NY Times on 4 May 2009 an article entitled "A Guy, a Car: Beyond Schizophrenia". http://www.nytimes.com/2009/05/05/health/05case.html.

The delimma is should a patient with a specific psychiatric disorder on a specific medication be okayed to drive?

While schizophrenia may increase the likelihood of an accident, research in the 1980s by Dr. Russell Noyes suggested that, among patients with psychiatric disorders, those with alcoholism and antisocial personality traits accounted for most of the risk. The Utah Department of Public Safety asserts that most people under active treatment for schizophrenia are “relatively safe” drivers, and clearly says that one’s accident and violation record is a better predictor of driving risk than is a psychiatric diagnosis.

Still, drugs like clozapine can impair driving skills. And the doctor’s-office-based assessment of a patient’s driving skills is only moderately correlated with scores on standardized road tests.