Well, I found out what it is. 1 unit in all 3D GTA games = 1 Meter. I found out that the streets are 20 unit's in total. So now I have what I need to get the road and stuff started. And then I'm going to work in. Yeah, it's a 1 man project for now. And later I'm going to need a good mapper, for displacement. Thanks.
I really need to know the scaling for GTA 3. Basically what I'm doing is making GTA 3 in Valve's Source engine(Half-Life 2). And I need to know what the units equal, like with Source 1 unit = 1 inch. And without knowing the scaling then it could be way to big, or way to small. If I mess up one thing I would have to edit a lot. So I really need this info. Any help would be amazing. Thanks.