Lots of people in my Seattle office ride their bikes to work and rid them after work as a form of exercise. Google launched mobile biking directions and navigation, including turn-by-turn, voice-guided navigation to Google Maps Navigation (beta) for Android smartphones. With a bike mount hooked up you can see and hear voice-guided direction in locations around the world.
You may have seen the biking directions symbol on your phone before, they added it in 2010, but this update brings the full driving experience to the biking option in Google Maps Navigation. Dark green lines show trails and paths with no motor vehicles, light green show streets with bike lanes, and dashed green lines show other recommended biking streets. Google stated that this updated biking service even helps you avoid steep hills if you want.
You are also encourage to use Google Map Maker to add bike trails and other features to enhance the biking experience. Be careful out there on the road with motor vehicles.