Sausalito has passed a plan to "ease the bicycle crunch", including posting signs advising cyclists to "ride single-file". Unfortunately, it's not so simple: cyclists are not required to ride single file, no matter what law makers or enforcers whould like you to believe. Therefore such signs would be misleading. I propose the following, instead:
This does a much better job of describing what cyclists must and should do on the roads. Which when you're riding the speed of traffic on a narrow road, has nothing to do with being single-file.