When I'm trying to figure out if I can bike to a new location, I log into strava (free to register an account) and go to the strava heat map. https://www.strava.com/heatmap#3.00/-120.90000/38.36000/gray/ride
They've got 700 million activities logged by users there, though I'm not sure how many of those are bike rides, vs. walks and jogging, etc. Anyway - you can filter by bike rides. I like putting the settings on gray, rides, 60% opacity, maps and labels. You can zoom into any city and get an idea of how and where people are riding. If an area is "hot" - you can assume it's relatively safe and heavily used by cyclists. For me it's handy because I can see where people are crossing major highways, instead of guessing how I should get across. Or looking at my neighborhood now, I see the N/S street two miles west of me is lit up, so without even going over there myself I can tell you it has the best side walks.
That is INCREDIBLY cool. And helpful!! Thanks!!