Epilepsy, Driving, And My Son

My son and I were talking the other day about me not driving.  Here's the conversation:

Son:  Mom, they need to make a car that drives itself so you can drive places.  It would know when to stop and to pass cars and everything.

Me:  That would be one expensive car.  I'd never be able to afford it if they made one.

Son:  Well, they should make something for people so they could drive.

Me: Actually; they do.  It's called a Hummer.  That way you go over things instead of hitting them when you have a seizure.  *feeling pleased with myself for the joke* 

Son: *pause*  Can we get you one?