There are no usable ramps, so he can't get down.
Eh? What makes the ramps unusable? [EDIT] Googles "unusable ramp". [/EDIT]
OK, I see. So it looks like it's impossible to include the top of that corner in my 3x3 road unless I mess around with faux-bridges to replace the walls I can't build there.
Now I'm wondering how much of my 'road' wagons would actually be able to travel along. :-(