I believe that 5 and 11 may actually be connected
I think there were some signs on the corners that indicated that
Pictures? I don't remember any myself, but could be wrong.
Also, just because there are signs indicating that SSR5 and SSRR11 may be located in close proximity in an imaginary city, that doesn't mean they ever were, or ever will be, actually connected together in the manor that most of us would wish for.
For an example of this, go on SSR5 in GT6. The the first long tunnel (left hander), there is an exit ramp on your right. Check the signage...it clearly says "Route 7", indicating that Route 7 might also be located in the same fictional city. But I see the signage as an environment modelling detail (much like the monkey and Nessy on Trial Mountain, or other little Easter Eggs), and not foreshadowing a massive "Special Stage City"
This vid shows a lap of SSR11 from GT3.
At 25 - 35 seconds, he is in the hairpin which many have proposed would connect SSR5 and 11 together. Ask yourself whether or note the environments actually match.
- SSR5 is located in the city center, SSR11 seems much more industrial (note the crains in the video).
- SSR5 hairpin is in a parking lot, whereas SSR11's hairpin is on an actual road (which follows the path of a hairpin...very unrealistic).
- SSR11 hairpin goes under an overpass. If it were connected to SSR5 at its hairpin, that overpass would lead directly into an office building. There is no corresponding elevated roadway on SSR5 to connect to.
Again, not saying that we can't dream of connecting the two tracks...I just don't think there's currently any evidence which suggest that PD has any plans or desire to do so.