Yes. But you must have a prescription of the psychostimulants from your doctor. Otherwise a drug test of your urine might show the psychostimulants and you can get in serious trouble with the police.
There is ongoing research in the area of driving performance and ADHD. Up to now most scientist have no doubt that you will show a better driving performance if you take medicine. But you should also consider that your attention and awareness can differ extrem. If you are not used to the "new" perceptions of your enviroment (at the very beginning of a psychopharmacological treatment) you should not drive a car.