Originally Posted by
Gresp15C
My impression is that Google estimates cycling trips at a constant 12 mph, whereas their algorithms for car trips seem to take prevailing conditions into account. For me, these are both fairly realistic. Traffic affects my overall speed when I'm in a car, but has little impact on how fast I can get somewhere by bike. I always trust my bike to get me somewhere in my little hamlet, even when there's something like a home football game, rush our, or the occasional riot.
Here are two Google cycling time estimates on a half-mile hill, one up and one down. Going up is 5 minutes, down is 2 minutes, so it's not a constant estimation and it does take into account grade.
The cycling estimate does NOT take current traffic into account though, that I can tell.