An Americanized Dutch intersection

The video embedded below was produced by Nick Falbo for a design competition at George Mason University. Mr. Falbo is now employed at Alta Planning and Design, a leading design firm which promotes and designs special bicycling infrastructure.

Protected Intersections For Bicyclists from Nick Falbo on Vimeo.

This is an impressive example of video art, but the video image and narration are far from telling a complete or unbiased story about the design. This article is an attempt to counterbalance Mr. Falbo’s claims.

The video starts with an animation showing motorists and bicyclists all tailgating each other — unrealistic and fear-provoking. Conventional bike lanes and shared-lane markings are shown, and dismissed out of hand.

The accompanying narration says “sharing busy traffic lanes with cars is absolutely unacceptable” and “we know that protected bike lanes are the key to getting the average person to consider traveling by bike.” Like most absolute statements, these are inaccurate. The royal “we” invites the comment, “who, me too?” What other keys are we leaving off the keychain? Other infrastructure treatments? Decent weather, reasonable distances, secure parking, education, strict driver licensing and enforcement?

The video shows an intersection converted to the proposed design, losing right-turn lanes and so, traffic capacity — but that is never mentioned.

“Protected bike lanes” sounds inviting, but that’s inaccurate too: these are paths, not lanes. And, in traffic engineering, the word “protected” does not mean “bicyclists have a crossbike, the way pedestrians have a crosswalk.” It means that conflicting traffic movements are separated in time by traffic signals. Contrary to the title of the video, then, this is a protected intersection only if special signal phases prohibit motorists from crossing bicyclists’ line of travel — increasing delay. Except with these options, motorists must yield to bicyclists after turning the corner.

Pulling the bikeway away from the street so motorists must turn before crossing, as shown, does make it easier for motorists to see and yield to bicyclists overtaking on the right. That’s important because the design excludes normal merging before reaching the intersection: bicyclists and motorists must instead cross paths in the intersection. Crossbikes are, however, indicated feebly in the video only with dashed border lines, while the crosswalks behind them are indicated with bold zebra stripes. If more than one motor vehicle is yielding to a bicyclist, then all others behind have to wait.

The claim in the narration that “setback crossings provide the space and time for everyone to react to potential conflicts” is inaccurate. Motorists approach bicyclists from behind and to the left, so the bicyclists must either take it on faith that motorists will yield, or crane their necks and be prepared to stop.

Waiting space for bicyclists is limited. Walking becomes more challenging because pedestrians must cross the bikeway, then the street.

This video, its precursors and successors have also been discussed at length on Mark Wagenbuur’s BicycleDutch blog. Please read his blog post, and my response below.

Wagenbuur endorses Falbo’s design, though he criticizes Falbo’s explanation of some of its features, and quotes Dutch traffic engineer Dick van Veen about the waiting area for right turns: “It is right before the crossing place for people walking and cycling, but it is at the same time out-of-the-way from straight going motor traffic.” — a more positive interpretation of my own observation that if more than one car — or a long truck or bus — is waiting to turn right, then all traffic behind must wait.

Wagenbuur also goes on to criticize problems with various copycat versions of the Dutch design, and to point out alternatives. I agree with most of them but disagree with one claim, that a roundabout takes up less room than a conventional intersection. You might notice in the “before” overhead view in Wagenhuur’s blog post that one of the streets has a wide, landscaped median and the other appears to be located in a linear park. The extra space is taken up by bikeways which are set far back from the streets. The larger context of the intersection is visible here in Google Maps.

To sum up, Falbo’s video makes inaccurate claims, and also, the proposed design affects traffic capacity, delay, space requirements and safety in ways which he dismisses or ignores. Designs like this are buildable and politically feasible at some intersections in the Netherlands, where the political constituency for bikeways is strong, driver licensing and enforcement are very strict, motorists expect to yield to bicyclists on their right, and crossbikes are indicated with shark-tooth yield markings. To promote a design like this in the USA without considering the downsides and without those other criteria being met is to put the cart before the horse — to recruit citizens into an attempt to to force culture change through infrastructure change — but also to ignore many potential infrastructure alternatives such as Wagenbuur’s blog also discusses, ranging from creating a bypass for through motor traffic and reducing speed limits on bypassed streets, to grade separations, to identification of another quieter parallel street which would make a great neighborhood greenway.

14 responses to “An Americanized Dutch intersection

  1. If large trucks are making right turns at this intersection (or even left turns) there is an excellent chance that those refuge islands will be overridden by the trailer wheels of a tractor trailer, or even the trailing wheels of something like a garbage truck. Also, it seems that with the angles and space of that intersection, trucks making left turns would have to override oncoming lanes and encroach into oncoming traffic space.

    Agree that this design, if done to truly protect cyclists, requires signal timing to prevent turning and crossing conflicts, even with the alleged better visibility of cyclists due to the advance stop line in the cycletrack. Thus, seriously decreasing both bicycle and motorist level of service.

    • Is there no limit to the amount of distractions that people will continue to throw into this for no valid reason beyond just to be an obstructionist? This one about trucks is yet another. The usual implementations of this intersection design result in the stop lines being moved back quite a bit from the travel lines of the intersection. Between the bulb-out, cycletrack, and crosswalk, the stop bar is going to be at least a good 20′ back from the intersection. Furthermore, as is seen in the Falbo video, the left turn pocket is often set back another car length, which is another 20′ or more on the ground. That’s a lot of space, and as can be seen in Wagenbuur’s video, vehicles bigger/longer than trash trucks still easily make the turn without running over the island.

      As for level-of-service, that’s not as much of an issue in CA anymore. But it doesn’t have to mean that all traffic grinds to a halt. Like the road network in general, many intersections are built for peak hours but are vastly overbuilt for the rest of the time. As it is, bike lanes don’t necessarily lead to congestion. So it stands to reason that if an intersection currently operates at level B or even C during peak hour, there is still plenty of opportunity to insert a bicycle phase in most of those without majorly inconveniencing the rest of the road users. Also, as can be seen in the video from Wagenbuur above, upgrading can allow for the phasing to be more responsive to actual needs and offer a better LoS to all. Another tool available (though still “experimental” in America) is an ‘all-directions green‘ phase for bicycles. Even in a traditional cycle, two ADGs can be included without drastically decreasing the LoS. All of this ignores that high-quality infrastructure attracts riders, potentially lowering the number of cars on the street which, surprise surprise, also improves LoS.

      • Level of service not a problem in California, which is to say, no traffic jams? No problem in setting back stop lines (it increases delay and prevents drivers from seeing what is approaching in the side streets — they have to stop again to do that) — excess capacity between peak hours solves congestion problems in peak hours? I’m not impressed. But above all: most of the people here, whatever their opinions, are discussing particulars and trying to figure out how things work. You attempted to trivialize other people’s comments, and imputed motives: “distractions” and “Just to be obstructionists.” Any more of that kind of crap and I’m going to block you from this blog.

        • No one said there would not be traffic in CA. But the fact remains that LoS will no longer be the (only) metric used to make decisions concerning roadway design and expansion in the Golden State. Like it or not, those are the facts.

          Also, if this is supposed to be about solutions, let’s have solutions. Saying that trucks “can’t turn” is only observing a potential problem and no solution was offered. Truck routes aren’t exactly secret. A designated truck route or a road where one would reasonably expect to find trucks should clearly be designed to handle trucks. Stop line setbacks are an actual solution to that problem. Setting the lines back does not discharge drivers of stopping behind that line when faced with a red light or exercising due caution before proceeding through the intersection. If there really isn’t room for adequate sight lines to safely proceed, then add ‘No Turn on Red’ signage.

  2. Actually the problems are even worse than that.
    The claimed improved visibility given by the forward stop bar assumes that cyclists and drivers arrive at the junction while the light is red. If a cyclist arrives while the lights are on green they will be moving faster than the car (which will be slowing for the turn) thus approaching from behind the driver’s right shoulder and hidden behind parked cars.
    The claim that the car turning 90 degrees before crossing the cycle crossing helps visibility is also bogus. Cars cannot stop instantaineously – the driver needs to be hitting the brakes before they have started to turn – at which point the cyclist is behind them – moving faster and with a shorter distance to reach the crossing.
    It is claimed that the effective corner radius is “small” – but the geometry of the junction shown in the video is about 12m, which I would describe as “excessively large”. Though the corner radius faced by right turning cyclists is very tight.
    The only way such an arrangement could be made remotely safe is to have completely separate signal phasing – which would mean cyclists held up on red for most of the time – even when the parallel traffic lane was on green. Some of the proposed staging arrangements would simply lock up the junction completely – for example having a separate stage for right turns and straight ahead traffic when you have removed the right turn lane.

  3. What strikes me about these “PBL” designs is that the motorist, at the intersection of Streets A an B, once having turned off A onto B (right or left), should be considered a motorist traveling forward on B–and the usual rule of the road would be that someone traveling on a lesser roadway that intersects with B should yield to the motorist on B. Read the “bike path” parallel to A as one of those lesser roadways. Both the motorist and the cyclist should consider the motorist on B to have the right of way and the cyclist alongside A should yield. The “PBL” design tries to flip that usual rule on its head. Different rules in similar circumstances “yield” more mistakes. Separate signalization is essential to the design’s safe use.

    Pedestrian crosswalks are a different case considering the relative ease of pedestrians to stop, change direction, and even observe turning traffic. But then note how many pedestrians using crosswalks are struck by motorists. Copying the pedestrian crosswalk concept over to a bike crossing is completely inappropriate because it can be expected to yield a cyclist accident rate more like the much higher pedestrian accident rate.

    What European studies have shown actually works for “PBLs” approaching intersections is to encourage the cyclists to merge into traffic ahead of the intersection, move through it with the other traffic, and then merge back into the “PBL.”

    • Actually, the rules of the road here in America (or at least here in CA) don’t follow as you think they do. A person turning from road A on to road B would have to yield to any vehicle on a road adjacent to road A (road C) as described in CVC 21800 unless signage exists that says otherwise. There are no distinctions made for major/minor roads in there, only for roads terminating in another. This situation is basically identical to the Dutch default priority which is to the vehicle on the right, though many of their intersections simply have no signage/signaling at all. While Falbo’s video makes mention of phasing rights separately (as does Wagenbuur), it doesn’t always happen. If you follow the link John posted to Wagenbuur’s write-up on the matter, the differences can be seen. In the first intersection picture, the ‘shark teeth’ face the cars on Road B and the red paving of the cycletrack has been continued straight through the intersection, both of which are used to indicate clearly to drivers on Road A intending to turn onto Road B that bicycles on Road C have priority. However, the second picture shows a car yielding to bikes when it wasn’t technically required. In that picture, it’s clear that Road B has priority over Road C due to the ‘YIELD’ sign facing the cycletrack, the ‘shark teeth’ facing the cycletrack, and the lack of continued red paving across the intersection. This means that bicyclists get to look out for their own safety while also not getting held up in long signal cycles. I couldn’t imagine that many American implementations would be done without a plethora of signs and green paint to jar drivers out of complacency. Of course, Google cars won’t get the whole yielding thing wrong at all.

      • The yielding rules can be set either way, so the traffic on the roadway must yield to the traffic on the sidepath, or the opposite, but the issues of sight lines, angle of view and increased delays still occur. It is going to result in less delay for merging to occur before the intersection (destination positioning) than for streams of traffic to cross in the intersection. The crux of the legal issue you raise is whether the parallel bikeway is to be considered a parallel highway. Actually, the definition of highway includes the cycle track and sidewalk — the entire width between the property lines, so the sidepath is not a parallel highway.

      • Please view Observe the motorist’s error at the end. IMO, the intersection treatment in the Falbo video would be all the worse as the turning radius leads to higher turning speeds.

        • The biggest issue is that some agency puts up something that is mediocre at best in the grand scheme of things, but is far enough ahead of everyone else to be “innovative”. That cycletrack in the video is one such implementation and what we should all vigilantly guard against. Not only does a travel lane suddenly end into it and require bikes to potentially weave through a stream of cars, but the visibility from behind those planters is horrendous. The intersections are also far from ideal and aren’t really similar to those in the Falbo video representation. One detail that Falbo didn’t really show is that Dutch cycletracks often are not perfectly straight through an intersection, but get bent away from the road ever so slightly to ensure that the crossing is at 90 degrees. The Vancouver situation is nowhere near that at all.

  4. On many intersections, the Dutch seem to be moving on from this design. Bike routes are often away from traffic completely so as to avoid intersections altogether. However, where cars and bicycles do meet at an intersection, the safest method, and one that is scaleable to most sizes of intersection is the simultaneous green for cyclists:

    • ADG junctions are fundamentally the same as the Falbo design. The difference is in the phasing. All bikes get a dedicated phase at the same time as opposed to going with the normal flow(s) of traffic.

  5. An interesting discussion is going on about an Austin, Texas, plan along these lines.

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