Bus relations can break at any time
by multimob — written on 2024-07-05
The Sisyphean nature of maintaining bus relations can be astonishing. If you complete a bus route relation, it can become invalid a few hours later. This is the sad drawback of an open platform where everyone may write. For the sake of the argument, we will only consider edits made in good faith by users, not vandalism.
What happened here? A user added a new roundabout, and drew some roads. The user made sure to connect the roads but did not realise bus route relations must include the roads. Now, the two bus routes coming here are broken. This is a very typical situation.
Finding where routes are broken?
How do we find out? We use the OSM Inspector’s "Public Transport Routes" view. The easiest is to filter and only show invalid routes. This is achieved by checking out the box for valid routes. This shows broken bus routes. Data is apparently refreshed twice a day.
Looking at this view on OSM Inspector is a good habit, to quickly find broken routes.
False positives with the OSM Inspector
There is an annoying problem with this tool. It also marks bus routes as invalid when they use "non-roads". This category includes roads that are unsuitable for a bus route. For instance, if a bus route uses a footway or a cycleway, it is wrong. This is good. But it also flags routes containing highway=construction as faulty.
Users apparently love retagging roads as highway=construction whenever there are construction works somewhere, because it renders well and is understood by routing software. We believe that this is wrong and that this tag should be reserved to new roads built in the middle of nowhere, not for works on an existing road. Yet, this is the dominant practice, and this is particularly true during summer months.
As a consequence, the OSM Inspector view mostly contains roads that have such a road that was retagged as a future road under construction. We take the view to inspect those once in a while and try to find if the road is open again. Information offered by public transport themselves can give a hint about whether the route is still diverted.
Permalink: https://blog.multimob.be/zzkae8nai9.htm