Parking lots waste a lot of area that could be green space too.

But yes overdevelpment could be a problem , but is easily fixed by adding a green space rule to development. Like we have now for minimum parking and such.

Also high speed roads destroy a lot of green space too, with nothing in the median or a good chunk on either side, and huge empty areas in dead zones of interchanges.

Lets not think cuurent car use is good for green space.