on my back porch i have the real smooth smooth conrete the kind that u will slip an fall an break ur neck if its wet but i take some chalk an draw the strait strecheswith chalk an take my zip zap track parts to make the turns with an set a brick on the outside edge of the track so it wont move if it gets hit and i throw a little sand on the track just to make things interesting
goin at it WRC style and when im done i sweep the sand up put it in a bucket for next time an collect my track pieces

an i can change the layout of the track when i want cuz all i have to do is draw new chalk lines
the sand dosent bother my car at all i just take some air duster you use for ur keyboard an blow it clean works like a charm