I worked in a pub 25 years ago, every Monday early to mid-afternoon a group of old gents would come in, we were late on in their day of drinking, some would make us their last stop, others would go on to another place.
They would be rocking by the time they arrived, including the one driving the car. He would be so drunk he could hardly stand, let alone drive a car.
Then I learned that the time they usually left was just as the local schools were finishing.
We also had an off-duty copper who sometimes popped in for a pint. So I said to him "what should someone do if they are concerned that a customer is drink driving on, say, every Monday afternoon at 3.30, in this area?"
And he replied "I think they could maybe tell a local friendly police officer".
So I said "that's what I'll do then" and then we looked at one another for a moment.
The drink driver got nabbed and lost his licence.
I'd do the same again in a moment if I had to.