I've noticed this in pictures from accross asia, including india, singapore, and myannmar.
This doesn't exist in European or American road signage systems.
Generally, the color of the curb indicates where or not you can park a car there and for how much time. It may also indicate if it is reserved for a dedicated veihcile type.
Not 100% sure in the case of Singapore, but the double yellow lines indicate no stopping.
For places where we are allowed to park on the sides of the roads, there are either lot spaces already allocated and drawn out, or there will be no lines painted on the road.
Double yellow lines in the picture here indicates no stopping at all times, so it would be a little pointless to have the curb indicate no parking again.
The curb might just be for visibility, can't confirm.
I suspect this is a remnant of the British era. Don't quote me on that.
In Belgium we have yellow panted stripes to indicate you're not allowed to park. Similar.