What assisted driving car is best for elderly drivers?

Dear all. Mom and Dad are in their 8th & 9th decades and both are still active and driving. However given their advanced age it seems some form of assisted driving vehicle would be best for them, with their personal safety and also prevention of fatigue being the primary motivation. They are US east coast based.

I am primarily seeking advice based on direct experience whether you chose for your own parents or if you are of similar age range and are the actual user/driver.

Thanks in advance.