Interesting Piece About Infrastructure and Pass Distances

[huskerdont]

“I have taken numerous rides with less experienced cyclists and have observed many of them riding in door zones”

I sometimes do a weekend ride with a well-known local shop. Road cyclists, some of whom race. I see some of them riding in the door zone fairly consistently through Alexandria and Arlington streets without bike lanes.

People, even those with experience, sometimes just aren’t very good at assessing the accretion of risk. (I suppose I’m not either or I’d commute some other way.)

[lordofthemark]

@scoot 189716 wrote:

By googling your quote, I assume that you found this article.

It seems plausible to me. I have taken numerous rides with less experienced cyclists and have observed many of them riding in door zones, even on low-speed streets with properly located sharrows or without markings at all.

On one hand, a drop from 85% to 45% sounds like an enormous improvement. It suggests that just a little bit of paint could sharply cut doorings on those streets. But it also sounds like that one data point was his “best” out of four separate studies, so should be consumed along with a huge grain of salt. The article itself is behind the Elsevier paywall.

I can’t imagine anyone believing that sharrows could ever eliminate door zone riding.

I do believe that properly located sharrows can help reduce door-zone riding and by extension dooring incidents. I also believe that riders who feel safer in a travel lane than a door zone are likely to experience more motorist harassment where DZBLs are painted than they would if sharrows were painted instead. (I have no data to support the latter hypothesis, just my perception of anecdotes from my own experience.)

To clarify, I agree that 85% to 45% is a net benefit. In places where there is no segregated infra possible, I do support correctly placed sharrows. I also support them in those places where the contraindications for DZBLs are strongest (and a PBL is not possible). IF a painted DZBL impacts driver door opening behavior (I have no data for that (beyond the absence of fatalities which is not strong evidence) either, but seems intuitively likely to me) it MAY offset the benefit of sharrows reducing door zone riding – and again, the presence of DZBLs may have other benefits in terms of reduced rear end collisions (not zero) traffic calming, etc.

[zsionakides]

@scoot 189716 wrote:

I can’t imagine anyone believing that sharrows could ever eliminate door zone riding.

I do believe that properly located sharrows can help reduce door-zone riding and by extension dooring incidents. I also believe that riders who feel safer in a travel lane than a door zone are likely to experience more motorist harassment where DZBLs are painted than they would if sharrows were painted instead. (I have no data to support the latter hypothesis, just my perception of anecdotes from my own experience.)

This is why I would prefer sharrows be painted instead of DZBLs if we’re not going to install PBLs or cycle tracks. There are some examples of painted bike lanes overseas where the driving area is narrowed to provide wide enough painted bike lanes, but that’s not what’s been installed here. Sharrows, while not good on higher speed roads, are better than narrow DZBLs and guide cyclists where to appropriately position themselves in the lane for safety.

[lordofthemark]

Another issue with sharrows and the VC approach generally, is scaleability. Sharrows “work” today, because there are not that many people on bikes and those who pick a route without seg infra are more likely to be faster riders. Imagine that instead of 2% mode share (5% in the District I guess) we had 10 to 20% mode share – but still lots of motor vehicle traffic. And that a large proportion of that 20% were children, elderly, people pulling trailers, etc. The conflicts with motor vehicle traffic would create issues – in some places worse than the conflicts created by seg infra.

[zsionakides]

@lordofthemark 189722 wrote:

Another issue with sharrows and the VC approach generally, is scaleability. Sharrows “work” today, because there are not that many people on bikes and those who pick a route without seg infra are more likely to be faster riders. Imagine that instead of 2% mode share (5% in the District I guess) we had 10 to 20% mode share – but still lots of motor vehicle traffic. And that a large proportion of that 20% were children, elderly, people pulling trailers, etc. The conflicts with motor vehicle traffic would create issues – in some places worse than the conflicts created by seg infra.

Increasing bike mode share, even with sharrows, tends to slow down traffic a lot. Look at Union St in Alexandria or Beach Dr in MD on the weekends as good examples where cars tend to drive slow due to the large volume of activity occurring on the road; though there’s plenty of unsafe actions at the low speeds.

20% bike share on the roads would completely change how drivers behave. The risks of hitting someone would too high to risk driving fast.

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