Recently, a fellow mapper (FinWonder) came up with the idea of highlighting dead ends: http://forum.openstreetmap.org/viewtopic.php?pid=299968 He posted some Python code here: https://github.com/KonstantinShemyak/no-dead-ends-OSM python markOSMBridges.py example.osm > marked-example.osm Unfortunately, the code is a bit memory-hungry; it failed to process the entire finland.osm (about 3 gigabytes, uncompressed from finland.osm.pbf) within 8 gigabytes of RAM. I think that this is a very interesting idea. I would even refine it further and split the 'dead-end graphs' for each mode of transportation: car, bicycle, foot, etc. For example, a way that ends in highway=steps is not a dead-end for pedestrians, but it is for everyone else. A highway=service leading to a fuel station along a highway=motorway is not a dead-end for cars, but is for everyone else. A way that ends in highway=path,access=no,bicycle=yes is dead-end for everyone except bicyclists. Short dead-ends (say, 10-meter or shorter driveways) should probably be ignored. While computing the dead-ends, the code could warn about 'major' highways that are dead-end, possibly because a T crossing with another way is incorrectly tagged (the junction node is not linked to both ways). Currently, mkgmap only complains about dead-end oneways, because that is much easier. Would this be feasible to implement in mkgmap? Or maybe better in a separate tool? I would guess that the dead-end way sections would be useful to be in separate layers that can be enabled or disabled on demand. Marko