If you’re getting sufficient sleep for your age/lifestyle and you’re still tired, especially while driving, I would strongly suggest talking to your pcp and see what they think.
They might reccommend taking a sleep test at a sleep clinic. There, they can find underlying sleep disorders that you’re not aware of.
Besides causing problems with your driving, if you really do have an underlying disorder, it might be affecting other areas of your life that you don’t even realize yet.
As for drowsy driving, I have narcolepsy and I know that I can’t drive at cetain times of the day/ night and that I can’t drive for time periods that are longer that 25-30 minutes or I start to get too sleepy to feel like I’m in the safe range. It’s not convenient, but I have a child and i have to keep both of us safe.
As you know— when you’re on the road, you’re not just dealing with yourself; you’re dealing with other people in their cars (perhaps with children, etc. in the backseat). You don’t want to ever put yourself, or them, at risk. A bad accident would be way too hard to live with.
Here’s a good link for a starter article on drowsiness: