I have a driving license. Personally I am capable of reviewing my fitness to drive. I actually don't drive because I get lost and there are too many external stimuli, I can't concentrate. Interestingly I score 100% on a peripheral vision test as that is just leds on a white background. In the real world it much more difficult to recognize things. I can't focus things out.
I don't think the driving test is a good test of fitness to drive, yet I couldn't come up with a better test. I passed the test after two failed attempts, which I failed because I was nervous. The difference in real life is there is not always someone there telling you where to go and many journeys are longer than the test.
Is there really a legal requirement to let them know about Asperger's? I don't think ASD in itself is enough to say someone can't drive it is specific traits that don't necessarily occur in everyone on the spectrum.