According to a new report from the San Francisco Metropolitan Transportation Agency, less than 10 percent of San Francisco's bike lanes are suitable for children or the elderly. Meaning: the city's bike lanes should come with some kind of warning label. (And definitely a helmet.)

In their quest to get everyone on two wheels, the SFMTA rated every bike route on a scale of 1-4, where a Level 1 is a leisurely spin through protected pathway in Golden Gate Park and Level 4 is a pothole-dodging, shit-your-shorts, doored-by-a-cabbie ride down Market Street. Level 1 bike routes were deemeed suitable for anyone ages 8 to 80 (everyone on the periphery of that should stick to driveways and stationary bikes, we guess), but only make up about 10 percent of the city's bike network. A Level 4 bike lane like Market Street, on the other hand, is only appropriate for what the MTA called "strong and fearless riders." But that's still no excuse to ride your bike on the sidewalk.

Of course, there's danger in encouraging "fearless" riding as well. You don't often see the timid ones blowing stop signs on the Wiggle.

Anyhow, the SFMTA plans to spend $30 million to improve cycling conditions around San Francisco in the next five years, but it would cost a cool $600 million to implement their ideal bike plan and ensure every bike lane feels like coasting along, propelled by good vibrations on a road paved with rainbows and dreams.

In the meantime, to work your way up to "strong and fearless," the Bike Coalition offers bicycle safety courses.

[SFMTA Bike Projects]