Challenged by the SF Transit Riders Union (SFTRU) to hop on Muni as much as possible for 22 days this month, the Mayor and Board of Supervisors are being carefully watched by that group as they do, or in most cases don't, avail themselves of public transit.

The above leaderboard shows that the Supes who accepted the challenge, along with the Mayor, are mostly finding their own way to City Hall. It's day 11, the halfway marker, and therefore also time to step up.

As Streetsblog explains, officials are to tweet photos of their rides with the hashtag #OnBoardSF. So far, that's led to some funny photo ops, like this #sefliefail from Norman Yee.

Others, like Jane Kim, make it look easy.

Ed Lee has made, or at least tweeted about, one trip on Muni so far during the challenge.

And Supervisors Scott Wiener and John Avalos are clearly the most committed to the cause.

Why 22 days? As SFTRU explains, it's "one day for each of the years since 1993 when San Francisco voters passed Proposition AA." That proposition's wording: "City officials and full-time employees [shall] travel to and from work on public transit at least twice a week."

As SFTRU is probably the last to point out, "22 years later, this policy agreement has never been acted on, and now is a chance to make up for lost time!"

Previously: Supervisors Help Kick Off 22-Day Muni Challenge With Rally At City Hall