It’s special parking spaces right near the entrance where you can drop off people. The idea is you drop them off right next to the entrance, they go in and you find a parking spot. That way they can be sure they are on time for their appointment, even if finding a parking spot takes some time. And people who can’t walk very well (which is more likely at a hospital) don’t have to walk from the other end of the parking lot to the entrance. It’s called kiss and ride because you are intended to park long enough to kiss them and drop them off, then ride off so the space is free for someone else. There’s only a finite amount of places, so staying as short as possible is key.

Sorry I thought it was a common enough phrase en.m.wiktionary.org/wiki/kiss_and_ride