barrier=kerb causing severe Routing errors on OpenStreetMap

[c-h-r-i-s-t-i-a-n]

Issue

barrier=kerb on highways is leading to routing errors.

Examples:

• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=50.82970%2C8.77314%3B50.82715%2C8.77159#map=15/50.8329/8.7697

• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=51.30117%2C12.39560%3B51.31054%2C12.39732#map=15/51.3056/12.4038

• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=48.70970%2C9.15362%3B48.71133%2C9.15267#map=17/48.71189/9.15724

Steps to reproduce

Use the Router "OSRM" on the osm website.

Specifications

Firefox-Browser

[c-h-r-i-s-t-i-a-n]

Note that none of the other routers on osm (valhalla, graphhopper) are showing this behaviour.

[c-h-r-i-s-t-i-a-n]

Also note that WIKI is suggesting access=yes as the default.

• https://wiki.openstreetmap.org/wiki/Tag%3Abarrier%3Dkerb

[osmuser63783]

This bug has led to quite a bit of discussion on the German forum.

In my view, failing to route cars over barrier=kerb with kerb=rolled is a clearly a bug in OSRM if we apply the Wiki definition that it's "traversable by large wheeled vehicles, such as cars and bicycles". This should be whitelisted, like kerb=lowered and kerb=flush already are.

It is less clear if it's a bug that OSRM won't route cars over barrier=kerb with kerb=raised. There is some disagreement about this one: where there really is a raised kerb on the road, drivers probably don't want to be routed over it. But the vast majority of barrier=kerb with kerb=raised are tagging errors. Fixing the data will fix all the examples Christian posted. Unfortunately this is not straightforward: the cause of the tagging errors is a bug in iD (related discussion), so we before correct the data, we should fix the bug in iD, otherwise they will just reappear.

[c-h-r-i-s-t-i-a-n]

It's not just a bug in ID. Some mappers find it okay to tag the kerb-barrier on the crossing node footway/highway.
There might also be some QM tools which are indicating nodes with kerb=* without barrier=kerb as an error.

[1ec5]

As of #5996, OSRM ignores kerb=* on a highway=crossing node along the roadway and also on a barrier=kerb node with kerb=lowered or kerb=flush. It would be appropriate to apply a small penalty to a kerb=rolled node, similar to a speed bump (#3021), but not to avoid it entirely.

osrm-backend/features/car/barrier.feature

Lines 49 to 59 in 41dda32

	# https://github.com/Project-OSRM/osrm-backend/issues/5996
	Scenario: Car - Kerb exception for barriers
	Then routability should be
	| node/barrier | node/highway | node/kerb | bothw |
	| kerb | | | |
	| kerb | crossing | | x |
	| kerb | crossing | yes | x |
	| kerb | | lowered | x |
	| kerb | | flush | x |
	| kerb | | raised | |
	| kerb | | yes | |

[osmuser63783]

I have removed barrier=kerb tags from many of these nodes because there was consensus that they are a data problem.

What is left for OSRM to do? In my view,

• barrier=kerb kerb=rolled should not prevent car routing entirely, a small penalty is appropriate
• it is questionable whether barrier=kerb kerb=raised should prevent car routing entirely, perhaps a large penalty would be appropriate?

[c-h-r-i-s-t-i-a-n]

Blocking: No. Penalty: Yes, but make sure that barrier=kerb is mapped on the actual position of the kerb and not on the crossing with the main road.

[c-h-r-i-s-t-i-a-n]

Some more examples (after the cleanup).

• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=53.56243%2C9.90883%3B53.56238%2C9.91002
• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=50.59466%2C5.88820%3B50.59423%2C5.88776
• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=53.45843%2C9.98460%3B53.46052%2C9.98152
• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=48.14659%2C16.29562%3B48.14755%2C16.29482
• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=48.81564%2C13.57644%3B48.81522%2C13.57581
• https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=43.31610%2C-1.40310%3B43.31712%2C-1.40388

[mjjbell]

What is left for OSRM to do? In my view,

• barrier=kerb kerb=rolled should not prevent car routing entirely, a small penalty is appropriate

• it is questionable whether barrier=kerb kerb=raised should prevent car routing entirely, perhaps a large penalty would be appropriate?

Thanks, I'll see if I can add this.

https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=43.31610%2C-1.40310%3B43.31712%2C-1.40388

I'd be interested to know if we think barrier=kerb is the correct tagging for this. It looks more like the kerb is for a pavement/viewing point, and would only be a barrier if it's used as an overtake location. Bit of a niche situation in any case.

[osmuser63783]

As far as I can see (without testing it), whitelisting kerb=rolled for cars only requires a tiny change in car.lua:
osmuser63783/cbf-routing-profiles@bb0fab0

(Shows here for cbf-routing-profiles, but it should be the same for the profiles in this repo)

I'd be interested to know if we think barrier=kerb is the correct tagging for this. It looks more like the kerb is for a pavement/viewing point, and would only be a barrier if it's used as an overtake location. Bit of a niche situation in any case.

This is the node. Maybe they were trying to say that you have to cross a kerb to access the passing place? Hard to say with certainty, but it's probably not the best way of tagging this.