- I would rename sx,sy,ex,ey to srcx, srcy, dstx, dsty, as they are more self-explaining;
- What exactly is left side of the street? Is this seen from src looking towards dst, or the other way around?
- Does stype also indicate the maximum speed allowed on that road? That would be interesting when calculating shortest route (in time it takes to drive there);
- In the struct you can't indicate a road is one-way only;
- Nitpicky, but still, I'd swap "size n" and "offset n" in geoline.dat;
- Could you also include the format for a single chunk? Don't feel like deducing it from geoline.dat :-P.
Other than that, looks very good .