Yes. First line of attack should be to experiment with improving the quality and/or quantity of your night sleep. If this happens to you mainly after you've been awake for 8 hours, try a mid-day nap.

If none of that helps, investigate medical conditions that might affect your arousal, be they psychiatric (depression, ADD) or physical (sleep apnea, eyes).

A possible remote third option is that you're frequently traveling as a passenger and allow yourself to use the riding time to rest, so your mind associates the running car with a resting place.

no joking: it is probably related to an eye issue, it could be that your eyeglasses formula is not correct or that you need to wear them if you don't have them yet.

Yes, came here to say this. I like driving alone but want to fall asleep almost instantly. Pulling over and taking a 10 minute nap is helpful.

try changing your cabin air filter.