Vehicles fall through newly constructed bridges

[TurfIt]

If a convoi encounters a bridge that was added after its route was calculated, it'll climb the ramp, then fall through the bridge deck and get stuck with 'no route' below.
Top left of the screenshot shows how the track was before the bridge added.

[prissi]

This only happens when there is a matching way directly under the first tile of the bridge. It is there since version 1 probably, since the route of vehicles is stored in (x,y,z) coordinates.

[TurfIt]

r7249 completely breaks bridges - vehicles won't transition from the ramp to deck.
I'd tried fixing the original problem before posting, but handling all the possible ground slopes and bridge ramp to bridge deck transitions was resulting in a huge mess of logic. Figured I must be doing it completely wrong, so posted to see if anyone else had a better solution...

[prissi]

This was a bad attempt avoiding get_neighbour. Using this everything seems fine, but the game runs much much slower. But I confined this check to slopes only.

[Ters]

Could the same happen with tunnels? And would the same fix take care of that?

[prissi]

Since it checks now connetions it could. But then is will have all sorts of troubles with curves before slopes.