With bike paths now too dark too early, many bike-riding commuters are back on the streets, flashing reflectors, sucking bus fumes and dodging slaloming taxis.

But there's another way home. Metro allows bicycles on the trains after 7 p.m. weekdays and all day weekends.

There is one obstacle, however: a test on the rules and regulations of bike toting. If you pass, you get a photo-ID permit you're required to wear while taking your bike for a ride.

How tough is it? Try answering these:

Are you allowed to ride your bike down the escalators, zoom to the end of the platform and do a wheelie?

Should you race handicapped people to the elevator, flash your bike pass and go first because you were there first?

Do you have to pay the fare if you're entering with a bike?

And can you take a motorized two-wheeler, like a Harley, on Metro?

After navigating my way through the 12-minute exam, I asked the test-giver if anyone had ever failed.

He pondered the question.

"Three."

In five years.

Out of more than 4,700 test-takers.

Randy Howes, bicycle coordinator for the Washington Metropolitan Area Transit Authority, couldn't remember why one of them failed. But he did recall that another did not know English and the third couldn't read.