I do have to admit I love the excitement of biking in traffic. Zigzag through all those yellow cabs makes my day. But sometimes the fastest and easiest way is to avoid all the jam and red lights. When I am off to the Financial District I actually take the river cycle track. Try it. For the someone not commuting - it is all worth it for the beauty. Just look at this low angle of Manhattan Bridge.
EAST RIVER & HUDSON E 18th St south and then north to W 50 St
safe to bike also in the evening or at night