Is it too much to ask my friend to stop texting when she drives?

I understand that I can't control her when I'm not in the passenger seat but I she constantly texts while driving, and says its okay because she can steer perfectly fine with her knee. She's gone off road several times and has gone into the other lane, luckily no one was coming from the opposite way. She's very stubborn and any time i ask her to change she gets upset. I'm tired of feeling in danger anytime I get into her car.