[seaerkin]

Any app that the majority of cyclists are using will win this battle. It's easy to map known bike trails, what's difficult is mapping a good road to bike on. There's so many factors that go into this, but the best and easiest way to get this data seems to be tracking what roads most cyclists are riding. This is exactly why strava heat map is the best for route planning IMHO. You can travel to any area and look at the heatmap surrounding you and instantly have an idea of what roads are heavy cycled.

[Mediterraneo10]

Strava is often unideal for touring, because its recommended routes are where all the local sports cyclists are forced to go due to their thin little tires and lust for speed. Tourers might have thicker tires and so be comfortabke with less smooth roads if it means avoiding cars.

[seaerkin]

That is a good point. I have seen Strava prefer a higher traffic road near me and I then manually adjust that portion. It would be cool if Strava could provide some sort of "Avoid vehicle traffic" preference when route building.