It is not a free track.
It should be the RCI track in Singapore which is inside Bottle tree park.
There are on-road track (not very big) and off-road track.
I went there every Sat ;)
(1) this one showed, off road + on road, at 'Bottletree park' (Yishun)
(2) on road track, at 'East Coast' near the airport, this one is rather big, quite nice
(3) Turf city, mainly off road for 1/8