It has to be a vehicle parking/turning area, though the logic of reasoning might be manifold.

Firstly, they might grant building permits on condition that no buildings are put on low-lying flood-prone areas, i.e. buildings are laid out such that these areas are occupied by roads, parking, etc. That's the "preventive" element.

Speaking cure, it might be that the hard-surfaced area is used to build a temporary water storage area. This has become big in France in recent years. Using coarse gravel or custom-made concrete elements as road/carpark/etc. foundation materials provides voids which can be occupied by water. Water feeds into these voids through special porous asphalt surfacing or through special drainage systems, and drains out through controlled apertures. By thus buffering water drainage, the systems allow drains and sewers to sized to more modest dimensions than if they were expected to handle the total discharge resulting from extreme rainfall events, with subsequent cost savings.

By buffering water beneath carparks, etc., the risk of flooding of adjacent buildings is reduced (without overengineering drains).