Sharrows need to be placed properly in order to be effective. They need to encourage bicyclists to control the lane — not try to share it side by side with cars as these did an which are dangerous. They should be centered between the tire tracks of where the cars typically go in the lane.

The people who say that sharrows don’t work are the same people who have never really put in the effort to properly study vehicular cycling, much less do the mileage using the techniques that you need to truly understand how it works.

The micro-mini “one-foot-wide blue hump” kind (which they have in the UK) are also pretty bad.

The small but not miniscule kind have their place.

There simply isn’t another traffic control device which *works* for those intersections. I’ve tried to use ones equipped with lights, ones equipped with stop signs, ones equipped with yields, and it’s a mess, confusion, danger, and crashes. The roundabouts work reasonably well.

Important to note: those intersections were dangerous for pedestrians *before* the roundabouts were installed. The roundabouts don’t make them any *worse*. The roundabout traffic is also very slow-moving.

If you’re laying out a street grid, you wouldn’t want to lay it out that way, of course. But if you’ve already got something like that going on, a roundabout makes sense.

The sharrows act as an instruction to drivers to *not* pass bikes on the left with no space at all, which is (sadly) what drivers tended to do without the sharrows. That’s what they’re good for.

I would never ever use them on a fast-moving road, and if you don’t put the arrow in the center of the lane, you’ve missed the entire point of sharrows.