Bright green lines indicate trails while darker green lines indicate bike lanes.

Because Google Maps lies about where bike facilities are. Check out the bicycling layer at 16th Street and Wood Street in Pilsen, Chicago, Illinois.

Google Maps bicycling layer legend

Google Maps bicycling layer legend

The bright green lines represent trails, but the ones in this part of Pilsen are not trails. All of the north-south “trails” you see are actually sidewalks underneath railroad viaducts. The east-west trails…well, I’m not sure what they are but they are on elevated railroad property. Don’t go up there.

I created my own bike map to deal with the inaccuracies across Google Maps. I used my local knowledge (“ground truth”) and high-quality bike facility data from the Chicago Department of Transportation.

I also used contributions to OpenStreetMap, mainly for trails. I’ve been correcting and adding new bike lane data to OSM as CDOT installs them. View this area with OpenCycleMap’s tiles, which shows only bike lanes on 18th Street.

If you’re an editor on Google’s Map Maker data editing platform, please correct these errors. I would do it except that Google doesn’t allow others to benefit from my data contributions like OpenStreetMap does, where anyone can give and take. (I also had a negative experience on Map Maker, getting myself into a tiff with an unnamed user who disagreed with my changes, based on a personal visit to the location, that were not visible on the satellite imagery because that location had outdated imagery.)