Talking to her when she's sober won't do jack...because nothing you do or say will ever change her. That's not within your power. Only she can decide to make any change.
However, I agree with shinethru:
1) Call the cops (I'd keep her license plate number and the make/model of her car handy)
2) Call CPS.
She is endangering her children's lives, not to mention the lives of those whose path she crosses.
IMO she needs to have her license revoked before she kills someone.