When to Use Protected Intersections? Academic Study Will Offer Advice

An intersection in Austin gives room for a driver to stop mid-turn while people bike past rather than putting cyclists in a driver’s blind spot. Photo: Greg Griffin

pfb logo 100x22Michael Andersen blogs for The Green Lane Project, a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets.

If 2015 was the year protected intersections arrived in the United States, 2016 is the year the country’s bikeway pros are starting to really figure them out.

Inspired by Dutch streets, protected intersection designs use a few simple tricks to rearrange traffic at intersections so that people on bikes and in cars don’t have to constantly look over their shoulders for one another.

Last week, Portland State University announced a $250,000 project that will use simulations to put people on virtual streets and test their use of protected intersections. The goal: create data-driven standards to tell cities where protected intersections are needed.

“At what traffic volume?” asked Justin Carinci, a spokesman for PSU’s National Institute for Transportation and Communities. “At what speeds?”

“We are thinking a combination of surveys, videos, and simulation will be needed,” Chris Monsere, a lead researcher in the project, said in an email.

Image: Nick Falbo/protectedintersection.com

Carinci said the study also aims to identify the “standard elements” of protected intersections.

“If you’re using this type, no matter where you’re using it, what do you have to have included in it?” he said.

Two years ago, NITC completed the first major academic study of protected bike lanes in the United States — research that has since informed their endorsement by the Federal Highway Administration and other institutions. Among many other findings, that study found that of the two most common intersection treatments for protected bike lanes — mixing zones and bike-specific signals — people feel much less comfortable in mixing zones.

Protected intersections offer cities a third way: more comfortable than mixing zones but potentially more intuitive than bike signals.

Monsere, Nathan McNeil, and Jennifer Dill, all researchers on NITC’s 2014 study, are part of the team for this study, too.

It’s due to wrap up in September 2017, Monsere said. As findings start to trickle out, we’ll definitely be covering them.

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  • I’m a little unclear on the statement:

    “Protected intersections offer cities a third way: more comfortable than mixing zones but potentially more intuitive than bike signals.”

    First, how are bike signals unintuitive? In the US they have signage all over them, but in most places, the placement and shape clearly shows the purpose, I’d say they’re fairly intuitive.

    But also, aren’t protected intersections often used with bike signals in the Netherlands?

  • Many drivers see the position of the bike signal and think its a turn signal and thus go at the wrong time. In the Netherlands, from what Ive seen, the signal is always at the near side not the far side so that confusion doesnt happen

  • HamTech87

    Aren’t the bike-only signals in the shape of a bike, like this?
    http://nacto.org/wp-content/uploads/2011/02/Project_CycleTrack_NYC-02.jpg

  • HamTech87

    Mixing zones are more like “2 ton steel bullying zones”.

  • BBnet3000

    Near-side signals are in the NACTO Urban Bikeway Design Guide and Interim FHWA guidelines. No idea why no one has bothered to use them in the US (someone feel free to tell me if a city has that I am not aware of), because they are really helpful.

  • Frank Kotter

    Thank you for stating this. I was unaware this is even on the RADAR anywhere in the U.S. as I never see it being discussed. I see this as one of the most important overriding design aspects which make EUR intersections safer for all users. (also costs multiples less in construction costs)

  • They are frequently used with bike signals in The Netherlands, but there are a significant number of Dutch ones that do not use separate phasing and they’re also used at intersections that don’t have any signals at all.

  • Relatedly, many bicyclists see the turn signal and confuse it for a bike signal–I’ve watched people almost get hit due to that little error. Almost all Dutch (and other European countries too) signals are nearside, not just the bike signals. That puts the stop bar much farther back from the intersection itself, which also why right on red is banned. In contrast, signals are pretty much required to be installed on the far side here in America, which in an increasing number of locations frequently means that they can be over 100′ from the stop bar. Standards call for supplementary nearside signals for installations over 120′, but that needs to be lowered to around 65′ for for bike signals.

  • They are, but the shape isn’t standardized and especially at a distance at night, looks similar to a turn signal.

  • Justin Carinci

    Appendix A of the report linked here has a good summary of the design of these: http://trec.pdx.edu/research/project/500/Operational_Guidance_for_Bicycle-Specific_Traffic_Signals

  • J

    It’s still amazing that we feel that we must try and study every single design option, before “discovering” that the one that’s been working for decades in the Netherlands (after decades of experimentation) also works the best in the US.

  • Good places to start:
    – Anywhere two bikeways cross, even just bike lanes
    – Any intersection along a street with a PBL, even if the intersecting streets have no bike facilities at all
    – Main bikeways where number of bikes is not at least half the number of motor vehicles
    – Near schools/parks/places where children or elderly will be found

  • this types of advices are very much important for all

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