How to map 4-month bridge replacement detour?

Question

I am wondering how I should temporarily (approximately a four-month period) map a designated/signed detour route due to an old bridge over a freeway being demolished and replaced with a new bridge.

Here is a link to the MnDOT detour map (there are actually two detours):

http://www.dot.state.mn.us/d6/projects/hwy52-hader-southbound-improvements/pdfs/detour1.pdf?utm_content=&utm_medium=email&utm_name=&utm_source=govdelivery&utm_term=

According to the OSM wiki, a route relation with route=detour is for PERMANENT alternate routes during traffic jams. This is not the same thing; it is temporary but 4 months long.

Thru-traffic on US 52 will simply be temporarily re-routed using the on- and off-ramps (motorway links already existing).

David

Answer 1

This is a perfect use-case for conditional restrictions.

If the bridge is closed for all types of traffic (motor vehicles, bicycles and pedestrians) and you (roughly) know the time-span for which this road is closed, then simply add the following tag to this road:

access:conditional=no @ (2021 Jul 15-2021 Nov 15)

If the bridge is just closed for motor vehicles but open for cyclists and pedestrians then add the following instead:

motor_vehicle:conditional=no @ (2021 Jul 15-2021 Nov 15)

You might have to adapt the date to your needs. Note that not all end-user software support conditional restrictions yet. In fact, the only application known to me is OsmAnd.

Answer 2

If it's closed for construction, then set the access to what it will be once it reopens, and then change highway=* to construction=*, and add tags like

highway=construction
opening_date=2021-11-30

(or whatever y-m-d it's expected to be open by). This method makes it easy to reopen, then all you have to do in JOSM is change construction=* back to highway=* and remove the opening_date=* tag. Programs like StreetComplete and Osmose will ask people if something is still under construction or flag it as being possibly completed respectively after the opening date.

highway=construction is not routable but is renderable on most consuming software, and it's not intended to be routable except by traffic destined for the worksite.

Answer 3

-2

For only four moths i wound just add some map notes, they are instant and can be removed just as quickly. alt text

I would not recommend changing the map data for such a short time. The change would be ok for the main OSM map but many derived maps use that data, and they will time lag so long that by the time they have reacted to the closed bridge it will be repaired and then there will be another time lag for them to show the restored route. I am looking at this from the point of view for a OSM on Garmin user. I don't know what commercial map providers like TomTom and Garmins do. They, i think, only do once a year updates and I guess they ignore short time closures and use dab or phone traffic alerts to cover this.

permanent link

answered 16 Jul '21, 07:40

andy mackey
13.2k●87●143●285
accept rate: 4%

edited 16 Jul '21, 07:56

3

I agree to not change the map substantially for this time frame. Scai has given a good solution how to do it with little unwanted impact.

I don't agree on placing a map note, though. In my understanding they are there to leave hints for mappers what to change in the map. That's why they can be "resolved", too. They shouldn't be used to give general notes to the public. The fact that they cannot systematically evaluated by any consumer alone makes them unsuitable for such case.

(16 Jul '21, 08:12) TZorn

How to map 4-month bridge replacement detour?

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