To be terrified for my DD

[Kittenrush]

I can't sugar coat it. My MIL is a terrible driver, she had minor accidents, bumps and scrapes all the time. She does really silly things like recently driving home with her handbrake on and almost setting her car on fire.
She has recently bought a car seat and wants to take my DD, who is currently 4 weeks old, on day trips ASAP. What on earth can I say? I feel like it's an accident waiting to happen.

Thank you for all your sound advice, DH is onboard so together we have started to plan what we are going to say. No pussy footing around the subject.
We are going to start by mentioning her safety in the car. Maybe suggest some extra lessons as others have suggested.
And on a personal note my New Years resolution is to be less of a wet blanket! It's about time really!
Thank you again you've all been very lovely