Because it's level and there's no traffic on it. No other road in our area fits that description. Why is there no traffic on it? Because it was bypassed by Columbia Parkway in 1937.
Meanwhile, out in Malibu, CA, there is only one street, period. It's the famous Pacific Coast Highway, and despite these less-than-ideal conditions, bikers are making it happen out there. I took this photo on a visit last month:
Fact is, people who bike, hike, run, climb, and surf in California make us look like wimps. So next time you hear someone complaining about bicycling conditions in Cincinnati, remember this photo, and know that there's not just one, but thousands of people in California who wouldn't even blink at whatever some Cincinnatian is complaining about.