I'm the sister of an alcholic. I'm his only living relative. So I recognise 'rescuer' mode. It's a situation I know well, and to my cost. Your friend might not be an addict, but to turn up at the home of a casual acquaintance at that kind of unsociable hour, not least having made the choice to drive whilst plastered out of her mind, suggests she does have a serious problem with alcohol.
And that's the problem with alcoholics. Their lives are invariably chaotic and they drag everyone else around them into that chaos. It's become yours. It's your home she was in; it's your colleagues who stand to be affected; it's your job that could end up on the line. But this isn't your mess. You can't allow it to become so. 'Rescuer' mode makes you susceptible to the peaks and troughs of their problems with addiction. You're sober, but you are suffering the symptoms by proxy.
If you're tempted to go into Rescuer mode again, remind yourself of the three Cs that anyone affected by someone else's alcohol problem should know. You didn't cause it. You can't control it. And you can't cure it. All addicts invariably do is drag you into that chaos with them. Unless this is a one-off, and I hope for everyone's sakes it is, you've taken on the mantle of Rescuer once. The stage is now set for a repetition of that pattern. What you need to do now is ensure this is nixed - immediately.
That's going to take rock solid boundaries. Effectiveness or otherwise of the police isn't the issue here: it's holding her accountabile for her actions. She's chosen to drive whilst inebriated. Reporting her could save her life, and it could safe the life of a totally innocent road-user or pedestrian. It could even be the sharp-wake up call she needs to get help; with alcoholics it usually takes a very serious episode: a brush with the law or bottoming out, for them to recognise the gravity of their condition.
This isn't your baggage, OP. It's hers. She's a grown adult, so leave it at the feet of the person to which it belongs. If you pick it up, or worse, try to carry it, it will bring no good either to her or to you.