simple answer - cause it’s implemented to do so… I am fully aware, that for road bikes the use of cycle-ways is mandatory in Germany.
If you want 100% legal routing in Germany - simply use the bike profile - have said that, forcing cycleways is in many areas result in “none useful” routing like this one:
(Switch over to the road-bike profile to see the difference)
here is another example:
The big difference are the resulting TurnInstructions! (and that’s IMHO the most important reason why I use the service )
As a reasonable road bike cyclist (when I am on the bike) I am judging for each road individually IF I will use the regular street - or the cycle way (if present) - and while I am riding and approaching a turn instruction I can transfer quite simple a street-based turn instruction into a cycle-way instruction. I have attempted previously do this vise versa - but failed so many times! - actually that was the main motivation to join the openrouteservice development team…
Last example - see the turn instructions here:
and compare them with the road-bike version…
Please assuming that you are not able to watch the map while you ride - just listening to the turn instructions have to be sufficient to find the right way.
The road bike profile still has somy odd behavior in my opinion as you can see here:
You can perfectly stay on the straight cycle way, but instead of that it takes a strange d-tour through the village which doesn’t make much sense in this case (imho )