In Germany it's often not IN cities, but around. Example for Frankfurt:

The's a metro ("S-Bahn") going north up to Friedberg/Hessen. Friedberg is the capital of the country. But there's no free "Park & Ride" there. Two stations towards Frankfurt you are in village called Wöllstadt. And there you have a free Park & Ride. More south some other village, no P&R. But then again in Bad Vilbel you have one.

Is however P&R + public tansport the fastest way to Frankfurt? That depends.

First, the Wöllstadt P&R isn't easily accessible from the Autobahn, or not even from the B3, which goes around Wöllstadt. And even when it went through it some years ago, it was several turn-left turn-rights through small streets.

And then the S6 only drives every 30 minutes to Frankfurt. It's supposed to change once they double the train tracks, but that will change. On top of it: metro lines don't have precedence, the quick trains like ICE have. So the S-Bahn more often than not waits until a faster train passes.

If it isn't between 7-9 in the morning, you're actually faster by car in Frankfurt than by public transport ... So the P&R is quite helpful for people living in the neighboring villages: they go by car to Wöllstadt, park there for free, commute to Frankfurt by metro. And that traffic jam free ... but not necessarily fast. And since parking in Frankfurt usually comes with a price tag, it's also a bit cheaper.

So it's nice to have this, but it's no all roses.