When to let others drive my child around

What age did you all start letting other people drive your child around?
Specifically considering grandmas, they are our daycare currently and I’m not sure about letting them take him places. He’s 8 months old currently.
With my mother I’m considered about safety, she can be a very distracted driver, I have been uncomfortable when in the car with her driving.
My mother in law, has somewhat limited mobility and I’m concerned about her getting him in and out of the car. I’m also concerned she will take him places just to show him off and be the proud grandma. She often is like this instead of being actually engaged and attentive.
In general what age did you start letting other people drive your kid around and also for my specific scenario, am I justified or being over protective?