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We all understand that it is human nature to lob softballs at arguments that support our individual paradigm and scrutinize those that challenge them. But doing so serves us poorly in the long run.

With the caveat that all I have to look at is the presentation which comes with obvious disadvantages -- I did not hear the verbiage nor could ask questions -- this falls short of an unqualified success. Or at the very least, good evidence of an unqualified success.

Briefly ...


  • What is the base for the percentage increases?
  • Why would 12% reduction in sidewalk cycling that spills over into a contra-flow cycle track be an improvement? It would still be subject to the same risk as sidewalk cycling.
  • If one goal is to increase safe cycling, why would an increase in the number of cyclists on 15th ST be so important and relevant to the overall amount of bicycling?
  • The veracity of the survey results depends on its design, response, and analysis. It appears that they interviewed people bicycling in the cycletrack. Low and behold, people that we observe using the cycletrack like it! We should question its applicability to the rest of the population.

The ROI looks pretty rough and is dependent on an assumption of relative safety. LAB courses, traffic research*, and human observation and its limits, all suggest that contraflow cycling is more dangerous. Fundamentally, a cycletrack does little to the interaction at intersections which is where most collisions take place.

Maybe I'll write more later -- babies are everywhere! -- detailing the points (as well as omitted ones) and using my English more carefully; but if LAB ... and presumably WABA ... safe cycling courses all teach that contraflow cycling entails greater risk and should be avoided, are we not being hypocritical pushing contraflow lanes and touting them as a success? Isn't WABA settling for a sub par facility when there are ways to transport cyclists in a fashion more inline with what everyone seems to recognize as safer?

** I heard about research paper on cycletracks in Montreal that claims that contraflow cycletracks pose no increased risk. But I have not read nor evaluated it.

Geof,

I would say it's a success for the simple reason that it meets the goals of the project; namely "to calm traffic, increase options for bicyclists, increase bicycle mode share, and serve as a pilot project for other similar bicycle lanes around DC." The results of this study show that it acheived each of these goals.

If you'd like to learn more about this study, you can find the methodology here.

"Why would 12% reduction in sidewalk cycling that spills over into a contra-flow cycle track be an improvement? It would still be subject to the same risk as sidewalk cycling." Not true. Shifting cycling to the cycletrack should avoid conflicts with pedestrians. It removes curb ramp navigation and other sidewalk-related issues. If your concern is the issue with turning cars, the additional signage should make for more cautious drivers and the removal of parking near the intersection makes for longer sightlines than at your usual intersection.


"If one goal is to increase safe cycling, why would an increase in the number of cyclists on 15th ST be so important and relevant to the overall amount of bicycling?" I don't really understand the question. What are you asking?

"It appears that they interviewed people bicycling in the cycletrack." Not exactly, they interviewed all people who used 15th: drivers, pedestrians, cyclists in the cycletrack, cyclists in the roadway and cyclists on the sidewalk, etc... If cyclists hated it, they would continue to use 15th, but shun the cycletrack.

"Fundamentally, a cycletrack does little to the interaction at intersections which is where most collisions take place." But this cycletrack was coupled with a road diet on 15th. That slowed down traffic and so THAT did a lot to change the interaction at intersections. It would be impossible to decouple these two changes, nor the other changes (signage, paint, etc...). And while most crashes do occur at intersections, not all crashes occur at intersections. So a reduction of crashes away from intersections is still a reduction in crashes.

"safe cycling courses all teach that contraflow cycling entails greater risk and should be avoided" But what does do they say about cases where contraflow cycling is done by design?...where the contraflow lanes are separated by 8 feet of space?

"Isn't WABA settling for a sub par facility when there are ways to transport cyclists in a fashion more inline with what everyone seems to recognize as safer?" DDOT is building more cycletracks, but not more contraflow cycletracks. I suppose a cycltrack with the flow would be safer than a contraflow one. I'm not sure by how much or if the contraflow lane is "unsafe." So far the limited evidence we have seems to indicate that it is safe. What we know is that the contraflow lane gives cyclists a option - going south on 15th without getting on the sidewalk - that used to not exist. For these reasons I'm not sure I'd call it sub-par. What makes it sub-par in your opinion?

While I'm highly skeptical of cycle tracks in general, I consider the 15th St project an overall success: 1) it significantly calmed motor vehicle traffic, 2) the cycle track was designed with some care and offers bicyclists a new option for (cautious) southbound travel, and 3) the cycle track is NOT a mandatory bicycle facility. What's not to like?

Unfortunately, I am having trouble viewing the html version of the document -- I tried clicking on the PDF link but it was reported as unavailable. The firewall and old browser do weirdo things to webpages. But (seriously) thanks for trying.

Generally speaking, we should consider the robustness of any study/estimate before declaring it knowledge. Moreover, we should also consider the magnitude of the effect as well as performance relative to alternative designs. And I'll note that my point is that declaring it as an unqualified success is a bad strategy.

I don't even know where to begin when critisizing the surveys. One of the surveys was declared by the author as unscientific and the other has little documentation. Survey methodology -- questionaire and sampling design -- is a tricky business and can have a meaningful impact on the estimates. I understand -- I have experience with this -- that surveys are quite expensive such that we need to do the best with what resources are available. But our use of that data should reflect that. For example, what population does this survey represent? Is this the right population for us to consider? Does the 112 respondents make sampling variability ignorable?

There is a difference between safe and safer. I'm unsure whether there is a well-defined idea of what risk level is safe versus unsafe. Consequently, I tried to carefully use "safer" since things like bicycle/motor vehicle speed as well as environmental factors all have some effect on the risk level but I argue that contraflow travel is almost certainly riskier with respect to collisions. Based on the literature on why contraflow sidewalk cycling entails more risk and how collisions take place, I fail to see how it doesn't apply here. The 8 feet of separation from the general flow of vehicular traffic is a bad condition since it places the (typically) much-faster-than-pedestrian cyclist out of the primary view of the driver. Moreover, the parked vehicles serve as a visual obstacle. Remember, roughly speaking, collisions don't occur when everyone is at their peak. Tom Vanderbuilt -- not his idea, but he would be the most relevant author off the top of my head -- described it as layers of swiss cheese where the holes need to line up for circumstances to be "right" for a collision. So you can have your paint, signs, and what not, but nonetheless I would argue that these would be low priority concerns versus whatever objects are directly in the field of vision for the somewhat distracted driver. I find the remark that LAB fails to make a specific distinction for "contraflow cycletracks with an 8-foot buffer" a bit disinegenous.** LAB probably fails to distinguish thousands of other subtle differences in the environment that might make for small changes in risk. Yet we still apply the ideas when the underlying rationale is applicable.

** There is a difference, of course. Pedestrians are generally expected on sidewalks whereas cyclists might be more expected on cycletracks if cycling traffic is high enough. With different expectations drivers may alter behavior accordingly such that theoretically dangerous situations still produce acceptable statistics ... think of the corner of Lee Highway and Lynn St/Key Bridge in Arlington.

Stating that discomposing the improvement among the components of the project is impossible is contradictory to the initial post. No? Clearly the project's effects can be modeled and you seem to have no problem accepting other modeled results from the analysis.

In regards to my comment on the amount of cyclists on 15th ST, it isn't clear whether the number of cyclists on 15th ST is a good measure of the increase in general cycling. That is, how much more cycling is there as a consequence of the contraflow cycletrack? Now seeing that there are cyclists using it over alternatives is probably a good signal; although some of the increase could be due to increased harrassment elsewhere. Clearly there is no metric for this alternative. So I don't give it a lot of weight even though Allen Muchnick has complained about other facilities creating harrassment -- the bike lane at the corner of George Mason and Wilson, for instance -- in his experience. Looking through the paper -- assuming that I found the right number -- suggesting a 40% increase in cycling on 15th ST as a consequence of the cycletrack is inaccurate. Isn't it a 40% increase in 2008 to 2009 bicycle traffic in the area with a modeled 24% increase in traffic on 14th and 15th ST? Of course, the paper does not differentiate the general trend from effects from the cycletrack. And 40% sounds a lot better than 87 bicycle trips ...

Anyway, I'm beginning to ramble and, unfortunately, I lack the energy and time to really collect my thoughts into an essay. But let me conclude with two ideas. One, if we fail to keep high standards for knowledge, we just become a shill for smart growth that few people will respect. Two, a thought on safe versus safer. I think that cycling is a pretty safe activity and that lots of general statistics support the idea. Consequently, even though contraflow cycletracks are built, it might certainly be the case that the risk level remains at an acceptable threshold. And if we really wanted to crunch some numbers, we might show that providing the facility increased activity and health such that whatever additional risk from the contraflow lane is more than offset. Moreover, that cycling is generally so safe makes it very difficult to differentiate relative risk in a short period of time. For example, if the risk of a reportable collision on this short strip is 1.0e-10/cycling-mile but the contraflow cycletrack increases the risk to 1.5e-10/cycling-mile it will take a long time and a lot of riders before ever statistically telling the difference between the two even though the risk increased 50%. I also understand that this might be the best politically feasible option at this time: I think that there is an order of magnitude difference in the cost of one-way motor vehicle traffic and two-way motor vehicle traffic. Nonetheless, if we accept enough sub-par facilities -- meaning that there is a reasonable belief that an alternative would perform better -- that differential in risk will begin to add up (how many severe injuries are acceptable?) and it might create situations hard to undo.

I think I addressed everything. If not, drop me a line.

Yikes! That was long. Sorry, I should have just held back and written a better crafted response.

Geof, the pdf is gone, and you're looking at a cached version of it. I bet you can get the original if you contact the author.

I never called it an unqualifed success. Those were your words.

The safety claims made by the study all relate to slower vehicle speed. I think that's a reasonable claim to make. The parked vehicle are set pretty far away from the interesection and do not create a visual obstacle.

Certainly the survey is of limited value, but it is not used to verify acheivement of any of the goals. In some cases it serves to back up other data, and as such it has more value.

Stating that discomposing the improvement among the components of the project is impossible is contradictory to the initial post. No? Yes. I should have stated that the redesign of 15th street was a success. Ideally they would have narrowed the road without the contraflow lane (just set up planters and stuff in that space). Studied. Than added the contraflow lane and studied. But we can say that the contraflow lane has probably moved cyclists off the sidewalk and given cyclists a new option (goal #2 of 4).

Your point to be critical of studies is well taken. And after finding the study online it seems less impressive (though I do think they make a case for having achieved all four goals, none of which is safer cycling, btw). Still I don't think this is a sub-par facility. Every time I've been on it, I've found many other users in that lane as well, so I'm not alone in thinking it adequate. What facility would be up to par?

While we should not accept sub-par facilities, we should not let perfect be the enemy of "good enough." Especially when each incremental improvement increases our numbers, and increase in numbers increases our power, and each increase in power increases our ability to demand "perfect". There is a quote I am mangling "to the outsider, the revolution seems sudden and unexpected. To the insider it seems plodding, incremental, full of false starts and setbacks. When you find yourself frustrated and ready to give up, that's when you know you're on the right path."

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