Road Kerbs are precast concrete elements used to detail driveways and car parks. Here are some of its uses:

Retain the driveway/car park/ foot path edge by preventing outward spreading.
Acts as a barrier/demarcation between road traffic/pedestrian or pedestrian footpath/landscape area.
Provide a physical check to prevent vehicles leaving the driveway.
Forming a channel along which surface water can be drained.