OpenStreetMap
osm.org/?lat=49.252838&lon=-122.907122&zoom=18
Deleted node.
osm.org/browse/node/814490914/history
Sometimes 'connectivity fix' scripts break things for routing. One case is due to human nature (not tagging a bridge for several reasons )
User 1 (me) adds a pair of trails, but doesn't specifically add a bridge.
User 2 (someone else) does a 'connectivity fixes' run, and ends up connecting 2 trails which aren't really connected.
This then results in a map website creating a route which has a user cycle halfway across a bridge, and then jump 50 feet below to a walking trail because it's a 'shorter route'.
I've since tagged that section of bike trail as a bridge, but have seen other issues where mapping websites generate routes that have users also jumping off bridges.
I think most of it comes down to human nature. You map out a track but forget, or don't realize that you actually crossed a bridge when riding.
Discussion
Comment from Vclaw on 6 October 2010 at 15:39
Worth checking your local area on keep right: http://keepright.ipax.at/
It warns of "intersections without junctions", ie places where ways cross without sharing nodes. So these should either have a junction, or a bridge/tunnel mapped.
I'd agree that is not helpful to do "connectivity fixes" in areas you are not familiar with, best to check on the ground if there's a bridge or not.
Comment from Sundance on 8 October 2010 at 20:03
layer= can help too, 0 is inferred and does not need to specified
0 ground
1 bridge
2 bridge on top of another bridge (freeway interchange for example)
-1 tunnel
Comment from mbiker_imports_and_more on 14 October 2010 at 06:44
Sorry for the "typo". I definitely have been around that place before, but may not remember the exact geometry by now.