Bridges variable elevation

General talk
1

Hi
I use the app Strava for recording my bike rides. It uses Open Street Map. It seems to me that the elevation for bridges is an issue.
When biking the elevation means a whole lot. I guess the elevation generally follow the terrain. But for elevated road construction like bridges this then comes out wrong if the elevation for the road is not adjusted.

The bridge Askøybrua is a suspension bridge. The top elevation for the road is 65meters. It starts and ends on 40 meters above sea level.
https://www.openstreetmap.org/#map=14/60.3947/5.2064

The bridge Puddefjordsbroen is 35meters at the highest. It starts and ends around 15 meters.
https://www.openstreetmap.org/#map=17/60.38358/5.31493

I am not into editing osm. Can anybody take a look at these bridges?

A fun fact is that these bridges will be used by the UCI Road World Championships in September 2017
https://bergen2017.no/en/

The bridge Sotrabrua will also be used. It is 55 meters at the highest.
https://www.openstreetmap.org/#map=16/60.3731/5.1647

2

Where does Strava get its elevation information from?

3

I think Strava gets its elevation information from topographic data. But I see that tunnels are registered right, or maybe elevating from entrance to exit in a straight elevating line.

4

OK, the “bridge” consist of several ways:

highway=primary|primary_link:
https://www.openstreetmap.org/way/40674804
https://www.openstreetmap.org/way/60909048
https://www.openstreetmap.org/way/4289055

All ways contain an ele-tag (“34” and “65”)

In parallel there is a highway=cycleway
https://www.openstreetmap.org/way/365183064
https://www.openstreetmap.org/way/365183065
https://www.openstreetmap.org/way/365183067
https://www.openstreetmap.org/way/365183072

Non of these ways contains a ele-tag.

So I assume the informaion about elevation for cycleways doesn’t come from OSM. There is a "“nvdb:id”=“xxxxxxxxxxx” tag on the cycleways which might be related to some kind of elevation informartion in another database.