I see you are about to meet to the idea, that the game have to reject the global map eventually and change it to the open persistent world, which would have almost limitless amount of space for driving (and more). There's only a few of things that is holding from implementing of this idea:
1. It would require all the game world to be redone;
2. The maps are currently too flat (which isn't a con for me, just like it wasn't a con for Arcanum, for example)
3. Possible problems described above (which can be easily dealt with).
So the main problem is that the map have to be redone manually (unlikely, because it's more than a bunch of work) or have to be generated by script (which is
already done, but it just needs some adjustments to fit our goal).
I think, that the 3rd described point may be solved by the own resources of the development team, or maybe we have to set up a coding contest or something.