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Killing Cyclists

2019-03-24 23:37:13.727726+00 by Dan Lyke 2 comments

In a recent conversation with city staff about the design for the repaving and restriping of Petaluma Blvd S., I mentioned that it's well documented that "sharrows" on the right side of the lane kill bicyclists. Studies from Chicago ( https://www.citylab.com/soluti...rastructure-lane-chicago/460095/ ) and Toronto and Vancouver ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519333/ ) suggest that sharrows probably don't do anything positive, but are actively dangerous to cyclists when placed on the right side of the lane.

I was pointed to the MUTCD, the Manual on Uniform Traffic Control Devices. It turns out that the Federal Highways Administration has a version of this, and California has a version of this. In the California version, the chapter that deals with "sharrows" is https://mutcd.fhwa.dot.gov/htm/2009/part9/part9c.htm#figure9C09

04 If used in a shared lane with on-street parallel parking, Shared Lane Markings should be placed so that the centers of the markings are at least 11 feet from the face of the curb, or from the edge of the pavement where there is no curb.

05 If used on a street without on-street parking that has an outside travel lane that is less than 14 feet wide, the centers of the Shared Lane Markings should be at least 4 feet from the face of the curb, or from the edge of the pavement where there is no curb.

Note that these are *minimums*, and that California DOT has various other documents discussing placement, several of which discuss rationale, including http://www.dot.ca.gov/hq/tpp/o...AC_SLM_and_BL_Best_Practices.pdf . These suggest much higher numbers, which generally put the sharrow in the center of the lane.

The general thought is that sharrows need to place cyclists safely outside of the "door zone", which they claim as 40" from the side of the car. It happens that both of our automobiles (a 1997 Ford Ranger and a 2014 BMW i3) have doors that extend more like 44" out from the side of the vehicle. But if a car is parked on the shoulder, 6" to 12" in from the white line, that suggests that the right edge of the sharrow should be at least 3' from the white line.

So let's look at a couple of places in Petaluma:

First is Mountain View Avenue at Olive. The center of the sharrow is 10'8" from the curb. This is definitely less than 11'. The shoulder here is a solid 9', so if cars park 6-12" from the curb you could, if you squint hard, make the argument that there'd be enough clearance... but yeah, come on out and look at how people park for yourself.

The second I street at 5th. This one is a little bit better, the center of the sharrow is 13'2", the shoulder lane is 10', so there's a little more clearance, but it still doesn't fill me with optimism.

The third picture is from I Street at Round Court, and this is why I rail against separated infrastructure: The shoulder "bike lane" is, at best, unswept, but the sharrows tell drivers that the cyclist doesn't belong in the lane.

If you were going to design infrastructure to kill bicyclists, this is how you'd do it. We should be livid that this shit got past city planning, and hopefully our new city engineer can shut this crap down.

[ related topics: Interactive Drama Photography Invention and Design History California Culture Automobiles Graphic Design Trains Race Bicycling ]

comments in ascending chronological order (reverse):

#Comment Re: Killing Cyclists made: 2019-03-25 17:30:28.028294+00 by: Mars Saxman

It always seemed to me that "sharrows" were an ineffective form of communication. There is so much ambiguity in the presentation. How, as a driver, am I supposed to respond to these marks? What kind of interaction is expected? Am I supposed to change my lane position? Why are we calling out the possibility of bicycles in this particular context - if bicycles are supposed to be treated as equal road users in all contexts save freeways, why is it important to think about them *here*, especially? Doesn't that imply that bicycles are *not* actually equal road users and that there are special environments with special rules needed to accommodate them? Which story are we going with here? Are bicyclists supposed to be riding along the axis of the sharrow, suggesting that what we have is a fuzzy-edged bike lane and a fuzzy-edged auto lane which sort of overlap, or is the sharrow trying to warn bicycles *away* from the interaction zone between parked and moving cars?

In sum, I think that the addition of sharrows to the streetscape actually removed information and clarity rather than increasing it.

#Comment Re: Killing Cyclists made: 2019-03-26 16:32:49.033445+00 by: Dan Lyke

The studies of actual driver behavior seem to confirm that your challenges are not unique...

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