but the simple one-direction ones are kinda stupid. If you want the top car, you have to unload all the others first.
Well, you need to have a very good relationship with the owners of the other cars

However, I can imagine it may work if you and your partner/housemate have their own cars and maybe also some of your children/other housemates. In that case this is a very cheap option to get the maximum out of a single parkingspot (and land could be pretty expensive, especially in dense urban environments).
And, ah, I get it. You mean there also could be fake roads (or overlapping tiles)
Well, not the overlapping thing.

That is indeed also an option (I believe GarryG already experimented with those kind of things with his houses/shoppingcenters). But not what I meant, as these require a tile next to the road (meaning that in dense urban areas you have to demolish a lot of buildings, or need to make a house/industry-set with parkingspots that overlap into a road). The good thing about this is that the actual road still can be used by RV's.
What I mean is indeed replacing the roads with fake roads (coded as objects/stationtiles), using the groundtile thing I mentioned before to make them automatically fit in with the roadset you chose.
This would mean that RV's will not drive over them, not always a bad thing, as sometimes I would like to force my RV's to not take the shortest route through a city, but make them use "main" roads, avenues or ring-roads so to say.
The really bad thing I just thought about could be that I believe that most houses will only be built when linked to an actual road, so this could have some impact on the cities (with houses disappearing).... That would need some experimenting...
The safest way to go (so that houses wont be affected) is either placing very small lots or spots (just one or two tiles, so that houses are still linked to an actual roadtile, like the ones in the screenshots you posted), or to have larger parkinglots surrounded by actual roads (and then houses around those).
But this is really up to the player to decide how he/she will solve the problem with possible disappearing houses, I may be overthinking this too much now at the moment

The very very best thing for this, would be a separate roadtype with parkingspots rather than pavement at the sides....... Lets hope that
this will keep on developing
