Originally Posted by
mr_bill
Bedford MA?
Welcome.
Anyhow, agree that the Chicago study is multiply flawed. Census block ACS data is beyond noisy. Further, primary means of transport to work is NOT a good stand in for who bikes in Chicago. And assuming people who LIVE next to sharrows are a good stand in for who bikes over sharrows.
The original studies on sharrows (which included Cambridge MA) are far superior even if they are showing their age.
Sharrows are worthless, of some value, or negative? It depends.
Sharrows on Cragie dam were near worthless. Sharrows on Oxford Street in Cambridge are amazing. Sharrows in Arlington Heights on Mass Ave are quite good. Sharrows on Essex St and Lincoln and "Surface Rd" in Boston are laughable, but not worthless.
To go negative they have to be placed on the wrong road -- too much traffic, too high a speed, AND/OR in the wrong place -- too close to the curb, especially too close to parking.
(BMUFL signs, worthless. Sharrows with BMUFL signs, not.)
So, finally, I'll notice that they are not just for the "3%." I've seen middle school kids riding alone over sharrows for short segments. Example, mostly ride on the Minuteman, but some distance on Mass Ave with sharrows. I've also seen parents with children riding over sharrows.
Warms my heart to see school kids in Lexington riding to school. Breaks my heart that they ride on the sidewalk because Marrett Rd is 40 mph.
Sharrows WILL NOT AND CAN NOT turn a high stress road into a less than high stress road. (Yeah, Marrett, 4/225, 62, etc. Sorry.)
-mr. bill
Nothing scientific to add, just personal observation agreeing with your impressions of the various routes you listed. I think the biggest difference I've noted is there seems to be a far less aggressive attitude on the part of drivers where there are sharrows, while the BMUFL signs by themselves might as well not be there.
That being said, sharrows on a busy 40 mph road (or higher) are likely absurd.