<human>: Can you summarize the given text in a few sentences?

This may be a little silly, and perhaps not the right place to ask, but I am about to go on a somewhat long drive with my good friend.  Her driving genuinely frightens me as she speeds, swerves and tailgates people.  We have carpooled to the mountain to ski together and I have been afraid for my safety.  

This time around she is doing me a huge favor, driving me beyond where she needs to go, but I also want to make sure I actually arrive at my destination.  I worry that there is a high risk for us getting into an accident with the way she drives.  I want to find a polite way to ask her to drive more carefully; I don't want to offend her or hurt her feelings since she's helping me out so much.
<bot>: My friend drives dangerously, I want to find a polite way to ask her to be more careful with me in the car.