Hi Satish, are you wanting a vegetable garden or a flower garden? A raised bed can be placed anywhere for gardening in a limited space. Here's an article: https://thekitchengarten.com/how-to-start-a-raised-bed-garden-2/
A raised bed garden is a good idea, you can also put a fence around the area youwant to plant in.
Another thought that coomes to mind is container planting , usually this is helpful when there is limited space, such as a patio area. The tyoe of plants that do well in containers are the bush type plants vs the pole climbing ones.
If the parking area water run-off is what you’re concerned about, then both of the above are great solutions.