Author Archives: jsallen

Europeans ride like this?

Check out this promotion video for Kickstarter funding, shot in Germany, or maybe Austria or Switzerland. The streets look German, and part of the narration is in German with English subtitles:

https://www.youtube.com/watch?v=pNs0ZQ_wzAc

The video shows three bicyclists. One of them is portrayed as a racer, and rides at speed on city streets. Here are three stills from the video:

At 0:31, our racer is riding in the door zone of parked cars, at high speed. It looks like he’s riding on the left side of the street but it’s the right side, where doors are more likely to open — driver’s side. The image is flipped: numbers on license plates are backwards, and the drivetrain is on the left side of the bicycle.

Bicyclist riding in door zone in flipped image

Bicyclist riding in door zone in flipped image

In the video, you’ll also see that he has just made made a left turn from the right side of a street where he also was riding in the door zone.

(This isn’t the only flipped clip in the video. Can you find the others? Weird!)

At 1.03 in the video, the racer is shown riding in the door zone, opposite the direction of traffic on a one-way street. Contraflow travel is legal on some quiet streets in residential areas in Germany, but then, this doesn’t look like that kind of street, and why ride in the door zone?

Bicyclists riding opposite traffic

Bicyclists riding opposite traffic

And at 2:13, our racer is shown making a right-hand turn into the door zone opposite the flow of traffic, at speed.

Wrong way

Wrong way

Northern European countries are often praised for including education about safe bicycling in the public schools. The popularity of bicycling in northern European countries is also supposed to improve cycling conduct there, through peer pressure. This video doesn’t fit that model. Can anyone explain why not?

You Gotta Be Kidding

The photo below is from MIT Spectrum, a publication of the Massachusetts Institute of Technology. The original caption reads:

Rotating between asphalt, grass and photovoltaic cells, spaces can dynamically shift from city street to park to energy source — on demand. If roads were solar panels, they could power 23.2% of Manhattan. Höweler and Yoon Architecture.

Image from MIT Spectrum

Image from MIT Spectrum

Uh, excuse me but how did my alma mater, a well-known engineering school, sanction the fantastic collection of impractical ideas? The street is supposed to be made of motorized, three-sided rotating panels and one side is photovoltaic cells? How long would that hold up? Energy costs? Expense? There have been proposals for solar cells in glass block-surfaced pavers on walking surfaces, probably doable, though expensive; photovoltaics have evenbeen suggested  as street paving — looks much iffier, but on the other hand, why would it make sense to put solar panels under the pounding wheels of vehicles in New York’s dark concrete canyons or even on rural highways when huge expanses of sun-drenched desert, or even New York City rooftops, stand open? Those wheely things over on the left of the picture? Aside from the difficulty of balancing and steering a monocycle, — it’s been tried (and you don’t have to go any farther than Wikipedia to see how impractical it is) — also, the rider’s pitching backward (“gerbiling”) in hard braking, how would one of these be stored in a New York apartment? It’s hard enough to store a folding bicycle!

 

Monsere, Dill et al. — Not Yet a Review, But…

M. Kary, who prepared a review of the Lusk et al Montreal study, has had a preliminary look at the Monsere, Dill et al. study of barrier-separated on-street bikeways (“cycle tracks”) which the bicycle industry lobby PeopleforBikes is promoting as demonstrating their safety. Dr. Kary has given me permission to publish his comments here.

An Introduction To and Overview Of:
Monsere C, Dill J, et al. (2014) Lessons From The Green Lanes: Evaluating Protected Bike Lanes In The U.S. Final Report, NITC-RR-583

To begin with a platitude: traffic accidents are rare events. The totals are large only because the overall volumes of exposure are huge. Therefore, if considering safety in terms of outcomes rather than the underlying mechanisms of operation, any facility, no matter how poorly designed, will appear safe if examined over a short period of time.

But collecting data over a long period of time has its disadvantages too: not just cost and delay, but also the averaging, and therefore blurring, of the effects of various changing causes and circumstances. Nor does it work at all for facilities that are yet to be built. In response to these problems, engineers developed the methods of traffic conflict analysis. They can be seen as based on the following logical and kinematic necessities. First, in order for a collision to occur, the vehicles involved must eventually get on a collision course. Second, in order to get on a collision course, they must first get on a near-collision course. On the other hand, not all vehicles once on collision or near-collision course do end up colliding: their operators make course corrections and avoid that outcome. Such potentially dangerous but often ultimately safe trajectories, i.e. traffic conflicts, occur much more frequently than actual collisions, deaths, or injuries. If there exists a suitable relationship between the former and the latter, then conflict analysis can be used to study road safety at reduced cost, with better timing, and even via simulation modelling of facilities that have been designed but not yet built.

The theory and practice of conflict analysis for motor vehicles has been developed over something like a half a century of research. This has evolved to quantitative methods using not just traffic cameras, but also instrumented vehicles, automated data extraction, and theoretical concepts such as time to collision, gap time, gap acceptance, post-encroachment time, and many others. There is no such corresponding body of research for bicycles. Even if there were, it could never be as important to bicycle or pedestrian deaths and injuries as it is for the occupants of cars and trucks: for example, the latter vehicles never topple over at stops or just slip and fall, so that their occupants fracture an arm or strike their heads on a curb. In fact the majority of bicyclist injuries, even those requiring hospitalization, apparently involve only the bicyclist, making conflict analysis entirely or at least largely irrelevant to them.

On the other hand collisions with motor vehicles are major factors in cyclist deaths and injuries, and they are what cyclists worry most about. And even apparently bicycle-only crashes can be provoked by e.g. general fears or specific intimidations, or avoidance manoeuvres leading to loss of control. Thus there are also dimensions of traffic conflicts applicable to bicycling, but either inapplicable or less so to motor vehicle-only conflicts. Nor is every conflict visible or strictly kinematic: consider for example the effects of sudden and loud horn honking or engine revving.

With these fundamental limitations in mind, obviously traffic conflict analysis is a promising method for investigating important aspects of bicycling safety. The theory needs to be developed, so we can figure out what constitutes a high or low rate of conflicts, what types of conflicts figure what way into which accident types, and how vehicle operators and pedestrians cope with them, such as through hypervigilance, or avoidance of the area and thus diversion of problems to a different one.

Not only does the theory need to be developed, but also the methods of data extraction and analysis: the subjective review of traffic camera recordings, typically of low quality, is a mind-numbingly tedious, labour-intensive and error-prone task, that does not scale well.

The work of Monsere et al. (2014), Lessons From The Green Lanes: Evaluating Protected Bike Lanes In The U.S., should be considered a pilot project in this effort, although the authors themselves do not describe it as such.

Monsere et al. aimed to address six questions:

  1. Do the facilities attract more cyclists?
  2. How well do the design features of the facilities work? In particular, do both the users of the protected bicycle facility and adjacent travel lanes understand the design intents of the facility, especially unique or experimental treatments at intersections?
  3. Do the protected lanes improve users’ perceptions of safety?
  4. What are the perceptions of nearby residents?
  5. How attractive are the protected lanes to different groups of people?
  6. Is the installation of the lanes associated with measureable increases in economic activity?

Apart from noting that, as with most sociological research, their survey response rates were dismally low (23-33% overall, counting even only partially completed surveys as full responses), to produce a socioeconomically skewed sample (e.g. the bicyclists being 89% white, 68% male, 82% having at least a four-year college degree, and 48% with annual incomes over $100,000)— this overview of their work considers only the first part of their question No. 2.

Monsere et al. installed video cameras along short bicycle sidepaths (“protected lanes”, “cycle tracks”) constructed between approximately the summer of 2012 and the early summer of 2013 as part of the Green Lanes Project. These were in four U.S. cities, San Francisco (two 0.3 mile paths), Portland (one 0.8 mile path), Chicago (0.8 and 1.2 mile paths) and Washington (a 1.12 mile path; no cameras were installed in Austin, although sociological surveys were conducted there). They did their video recording chiefly at intersections, six in these four cities in the summer and fall of 2013. This was then presumably while the users were still in a cautious or exploratory state, as they got used to the new facilities.

Only 12-18, or in one case 20, independent hours of video were analyzed from each intersection. As each intersection examined was given a unique treatment, results cannot easily be pooled. These are very small numbers.

(This makes for substantially less than 120 hours total. The authors seem to say they analyzed 144 hours of video at intersections. This would mean that some of this total came from multiple cameras examining the same intersection at the same time. The authors do show frame captures from some of their cameras. This observer would find it difficult to correctly identify the conflicts from the views on display.)

As noted following the opening platitude, any facility, no matter how poorly designed, will appear safe if examined over a short enough period of time.

The six facilities examined were all so new (less than or little more than a calendar year old) that there were no injury or death data available for them. (For comparison, the entire city and island of Montreal, with all its thousands of intersections, averages of late about five cyclist deaths and 25-50 police-recorded serious cycling injuries per year.) Thus, there would not have been a way to use even many more hours of recording to examine for any relationship between the surrogate outcomes (conflicts, violations or errant behaviours) and the outcomes of most interest, deaths and injuries.

Further, as this was neither a before-after study nor a comparison with standard intersections, there is no way to know whether the numbers of observed conflicts, violations, or errant behaviours, were themselves high or low.

As to the actual results from this pilot project, the much touted headline was that there were only six minor conflicts found, out of nearly 12,900 bicycle movements through intersections. The most basic problems with this headline are:

1. It is the wrong comparison. The conflict rate has to be the number of conflicts divided by the number of occasions where at least two users capable of conflicting are present, e.g. a bicycle and at least one other bicycle, pedestrian, or motor vehicle. Thus the authors give figures of 7574 turning motor vehicles, but only 1997 turning motor vehicles with bicycles present. The corresponding conflict rates (which they normalize by the products of bicycle and motor vehicle movements, not by the numbers of bicycle movements alone) they give for the individual intersections therefore vary by factors of approximately 3 to 10, depending on which figures are used.

2. Six is the total of observed “minor” conflicts, not the total number of observed conflicts. There were also 379 “precautionary” conflicts with motor vehicles, 216 with pedestrians, and 70 with other bicycles.

3. Besides conflicts, there were numerous violations or other errant behaviours: e.g. 9-70% of bicycles and 7-52% of turning motor vehicles in the various intersection designs used the lanes incorrectly, 1-18% of turning motor vehicles in the various mixing zone designs turned from the wrong lane, 5-10% of motorists turned illegally on red arrows at intersections with bicycle-specific signals, and 7-23% of bicyclists disobeyed their signals.

4. Without any theory or model of how any of these occurrences or their frequencies relate to death, injury, or property damage, and without any before-after or non-sidepath comparison data— not to mention, with the very small numbers of observation hours— there are almost no safety implications, positive or negative. The only concrete result is that one of the local authorities apparently deemed the problem of motor vehicles turning from the wrong lane (18%), straddling lanes (another 17%), or entering the turn lane early (15%) to be so severe that they later removed the intersection treatment and replaced it with another design (at Fell and Baker in San Francisco).

5. The sociological surveys tell another story: one-third of all bicyclists surveyed said they had been involved in at least one near collision on the paths, while 2% experienced an actual collision. 23% had a near collision with turning cars, 1.8% an actual collision with turning cars; 19% a near collision with a pedestrian, and 0.4% an actual collision with a pedestrian.

In short: this is an interesting pilot project, whose methods are impractical for the amount of data collection needed for meaningful safety results. Even with better methods, conflicts are only one facet of the bicycling, and overall safety picture; while road designers and road users, whether bicyclists or motorists, have to consider more than just safety. Convenience, transit time, cost, and greenhouse gas emissions also matter. A cycle track that, like the downtown de Maisonneuve track in Montreal, lies largely dormant in the winter, but delays motor vehicle traffic in the winter and ties it up spring, summer and fall, will be of no help in reducing CO2 emissions. The much touted headline results from this study are selective, overblown, and misleading. Any facility will appear safe if examined over a short enough period of time, and surely 12 to 20 hours each is short enough

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 design is an attempt at a US version of one type of Dutch intersection. The Dutch traffic control devices (signs, signals and markings) have been replaced by US versions.

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. 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 (before reconstruction, as still posted in June, 2014) and on Bing Maps (following reconstruction).

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.

PeopleforBikes promotes a new study

There hasn’t been time yet for a thorough review of the new study of barrier-separated bikeways on streets now being touted by the bicycling-industry lobbying organization PeopleforBikes, though claims of lack of traffic conflicts on these bikeways fly in the face of the experience of actually riding in them, and the results of earlier studies. The saying on the sign below is pertinent. Update, July 1, 2014: a quick “review preview” is now available.

The amount of energy necessary to refute bs is an order of magnitude bigger than to produce it.

A comparison

As is usual among advocates for such  bikeways,  PeopleforBikes uses the feelgood propaganda term “protected bike lanes” for them — though they are technically paths, not lanes, and are unprotected where most car-bike crashes happen, at intersections and driveways. PeopleforBikes cites three earlier studies as setting the stage for the new one, and offers a tepid acknowledgement of criticism of these studies, with a link to criticism of only one of them, along with an appeal to groupthink, and while reiterating the studies’ conclusions:

Three widely noticed Canadian studies, led by Harvard’s Ann Lusk, the University of British Columbia’s Kay Teschke and Ryerson University’s Anne Harris, focused mostly on safety. And though all three concluded that protected bike lanes greatly improve bike safety (28 percent fewer injuries per mile compared to comparable streets with no bike infrastructure using Lusk’s methodology, 90 percent fewer using Teschke’s; in Harris’s study, protected lanes reduced intersection risk by about 75 percent), they’ve drawn some thoughtful criticism for underexamining the importance of intersections, where most bike-related conflicts arise.

The three Canadian studies which PeopleforBikes cites have been reviewed, in detail, and demolished.

The study Lusk, A. C., Furth, P. G., Morency, P., Miranda-Moreno, L. F., Willett, W. C., & Dennerlein, J. T. (2011). Risk of injury for bicycling on cycle tracks versus in the street. Injury prevention, 17(2), 131-135, claims a 28% lower crash rate for cycle tracks in Montreal, relative to comparison streets. Flaws of the study include describing stretches of paths in parks and away from streets as cycle tracks; including stretches which had not been built yet in the reported mileage; selecting a multi-lane comparison street 10 blocks away with heavy, faster traffic for comparison with a cycle track street which is small and has light, slow traffic, examining short stretches which end just short of busy intersections; giving the length of one of the paths as twice as long as it is, halving its reported crash rate, and neglecting injuries to pedestrians. A detailed rebuttal and a link to the study online may be found here. Another review reaches similar conclusions.

Teschke, K., Harris, M.A., Reynolds, C.C., Winters, M., Babul, S., Chipman, M., Cusimano, M.D., Brubacher, J.R., Hunte, G., Friedman, S.M., Monro, M., Shen, H., Vernich, L., & Cripton, P.A. (2012). Route infrastructure and the risk of injuries to bicyclists: a case-crossover ctudy. American journal of public health, 102(12), 2336-2343. has been reviewed and debunked by John Forester. The central problem is that the one facility described in the study as a cycle track and used for comparison with all the others is a bikeway on a long bridge separated by a Jersey barrier, with no cross traffic.

M Anne Harris, Conor C O Reynolds, Meghan Winters, Peter A Cripton, Hui Shen, Mary L Chipman, Michael D Cusimano, Shelina Babul, Jeffrey R Brubacher, Steven M Friedman, Garth Hunte, Melody Monro, Lee Vernich and Kay Teschke, Comparing the effects of infrastructure on bicycling injury at intersections and non-intersections using a case–crossover design, 19:5 303-310 doi:10.1136/injuryprev-2012-040561, has also been reviewed and demolished. The comments published on the Injury Prevention Web site are a condensed version of the ones published here and here. An explanation of how they came to be condensed is here. The authors oddly found bicycle-only paths in parks to be 17.6 times as dangerous as bicycle-only paths in (or adjacent to) streets. They find multi-use paths in parks to be 22.8 times as dangerous as bicycle-only paths in streets; and riding in the street to be 20 times as dangerous as riding in a bicycle-only path in the street. These results are bizarre and contradict those of numerous other studies.

Note that the authorship of these two studies overlaps.

Teschke gave a presentation at the 2012 Velo-City conference in Toronto. I have posted comments on this presentation. My review addresses the deficits in epidemiology as an approach to the study of traffic safety, and also, specifics of the presentation. The graphics for the presentation display the preposterous result from the Harris study that bicycle crashes were 2000% as high on streets without cycle tracks as on streets with them, although the study also reports that more than half of all the crashes did not involve a motor vehicle. There are other absurdities. Also, it is clear from the authors’ presentation at a conference that they do not understand the definition of a collision, or intentionally skewed their data by describing single-bike crashes as collisions.

The authors of these studies flaunt their academic credentials, which may look impressive except when noting their errors of methodology and selection of data. These are not unbiased researchers: they are avid promoters of separate bikeways on streets, and the bias shows.

Fixie or track bicycle?

Track racing bicycle,from Bicycling Magazine

Track racing bicycle, from Bicycling Magazine. The caption in the picture reads “On a fixie, there are no gears or brakes. Only your legs control the drivetrain.”

From Bicycling Magazine, June 2014, page 28:

“A fixie (or fixed gear) is a singlespeed without brakes and without the mechanism that allows the bike to coast when you’re not pedaling.”

That is a description of a track racing bicycle, which is only one kind of bicycle with a fixed gear. The caption in the picture with the article repeats this description.

Let’s get definitions straight:

  • A fixed gear is a connection between the pedals and the driving wheel without a mechanism which allows coasting.
  • Antique high-wheeler bicycles have a fixed gear;
  • Children’s tricycles have a fixed gear;
  • Sturmey-Archer sells a three-speed fixed-gear hub, and so, some fixed-gear bicycles are not singlespeeds;
  • “Fixie” is not synonymous with “fixed gear”. Rather, “fixie” is slang for a bicycle with a fixed gear.
  • Fixed-gear bicycles for the road,  as a matter of common sense, safety and traffic law in many jurisdictions, must have a brake.

Though it is possible to slow a brakeless fixie by resisting the rotation of the pedals, this braking is not as effective as with a front handbrake, and can be lost due to the cranks’ outrunning the feet, or the chain’s coming off.

The photo with the Bicycling Magazine article shows a brakeless fixie on a street — illegal in many places, and with impaired safety due to the longer stopping distance and unreliability of braking. Also, the cyclist is using toe clips and tightly-adjusted straps with the end of each strap passed through the slot at the bottom of the buckle. The straps cannot, then, be adjusted while riding — OK on the track where a starter holds the bicycle upright, but not on the road. I have to wonder whether the cyclist in the photo was assisted in starting, or is being held upright for the photo by someone outside the picture.

Why am I taking the trouble to write this? Primarily, because the Bicycling Magazine article may induce people to take up riding fixed-gear bicycles without brakes on the road, and fumble with toeclips and straps, and crash, and be held at fault for crashing for lack of a brake. I am distressed that editors at Bicycling Magazine would pass on an incorrect description which generates confusion and might promote such behavior.

A thorough and accurate discussion of fixed-gear bicycles for use on the road may be found in Sheldon Brown’s article.

For the record, I own a fixie, shown in the photo below, and it is street-legal, equipped with dual handbrakes. If I had only one brake on this bicycle, it would be the front brake — but for riding with a freewheel, or on steep descents, I have installed a rear brake as well.

John Allen's fixie

John Allen’s fixie

Godzilla’s toothpaste decorates Seattle bikeway

A new bikeway has recently opened on Broadway in Seattle, Washington state, USA.

Someone has posted a video of a ride on the newly-opened bikeway.

(To get a better view of the video, click on “YouTube” and open it up full-screen.)

This is an uphill ride, very slow in most places. Traffic was light on the street, and even lighter on the bikeway. It will be interesting to see how the situation develops when traffic is heavier.

The bicyclist who made the video is clearly aware of the hazards, as he or she repeatedly checks for turning traffic before crossing intersections. Others might be more naive.

What most catches the eye though about this installation is the “Godzilla’s Toothpaste” barriers between the bikeway and parking spaces — an artistic touch, to be sure, though also a collision hazard, and sure to be pummeled by cars pulling into parking spaces. The toothpaste is visible a few seconds from the start of the video and also later.

As described by Seattle cyclist Joshua Putnam, the installation of the bikeway followed from a series of events, like a chain of dominoes falling over, except that some the dominoes were bicyclists. The first of these events was installation of a light rail line in the street. Then, bicycle crashes became much more frequent.

Light rail lines in streets are a serious hazard for bicyclists, from wheels’ getting caught in the flangeway, and from bicyclists’ having to choose their line of travel to avoid that risk. The problem is worsened by the tracks’ curving over to the edge of the street at stops — necessary so there can be a raised platform and wheelchair access.

To address the hazard it created with the trolley tracks, Seattle installed a two-way, one-side-of-the-street bikeway, on this two-way street. Such bikeways pose problems anywhere, due to the increased number of conflicts and unusual movements at intersections — but also much of Broadway is steep, and bicyclists traveling opposite the usual flow of traffic on the bikeway are going downhill. Crossing an intersection or driveway from right to left on the near side has been well-established as highly hazardous.

Before the trolley tracks, before the bikeway, bicyclists could travel downhill as fast as the motor traffic. Now, the safe speed is hardly more than walking speed, and with repeated checks for crossing and turning conflicts. As is the usual practice, large swatches of green paint have been spread on the street to demarcate zones where bicyclists and motorists operating according to their usual expectations are concealed from each other until too late to avoid collisions.

Motorcyclists also are at risk from the trolley tracks, but they are excluded by law from the bikeway.

Children’s abilities — focusing on peripheral vision

My previous post addressed children’s cycling abilities. I’d like to take the discussion a bit further here.

A conventional statement about children’s cycling abilities, as expressed on an e-mail list, is:

Children also have less than fully developed peripheral vision and are very poor judges of the speed of automobiles.

Pioneering cycling educator John Forester replied:

Presumably, it depends on the age of the child. Many of us have known children aged seven, who have grown up in cycling families, who cycle in accordance with the rules of the road for drivers of vehicles. The ability is there; it just has to be trained. I have taught classes of eight-year-olds who learned to cycle properly in the traffic of two-lane streets in residential areas. I fail to see much point in the peripheral vision worry, because all cyclists have to learn to look at whatever is going to be important; what’s out at the side has little relevance. As for judging the speed and distance (you need to know both) of other traffic, say automobiles, any person has to learn to judge whether or not there is time to make a movement or it will be necessary to wait. I’ve watched the judging skills of eight-year-olds improve as they practice various traffic movements. In my opinion, the people who express the concerns about such mental matters have not had experience in training cyclists; they just measure (or try to measure, or make assumptions based on irrelevant measurements, or …) children without any knowledge of what is actually required for cycling in traffic, and are therefore completely ignorant of how to learn the skills.

I wouldn’t have been as harsh as Forester, but I agree that reliance on data from research into mental or perceptual abilities, without actually measuring cycling performance, misses the mark. Abilities do appear sequentially, as shown for example in this paper. There are studies which show that the acquisition of skills in childhood can be advanced by a couple of years through training. The minimum age to obtain a driver’s license reflects a societal judgment of the maturity necessary to drive safely.

I think, however, that the claim that children of elementary-school age have limited peripheral vision is commonly misstated and misinterpreted. It isn’t that the range of angles of peripheral vision increases — as if a child’s retinas have only a small patch of sensory receptors at the center — “tunnel vision” — which expands over the years. I say this from my own experience.

What is importantly less developed in children is the conscious awareness of the peripheral visual field. It sends too much and too complicated information for the immature or untrained brain to process fully.

I recall a peripheral-vision experiment at school when I was 8 or 9 years old, checking how far to the side I could place my hand before I could no longer perceive the wiggling of my fingers. The angle was the same approximately 90 degrees as it still is 60 years later — except that I could perceive the wiggle but not yet the shape of the hand. From age 3, I rode a tricycle, from age 7, I rode a bicycle and from age 17 I drove a car, and did not fail to notice hazards in the peripheral visual field. Peripheral vision short of full, conscious perception, and like the spatial sense of hearing, serves to draw attention, so the eyes and head turn to focus central vision.

I learned to perceive my peripheral visual field consciously in my twenties. I trained myself by focusing my attention on objects in the peripheral field instead of turning my eyes to look at them. This can look weird in social situations! I undertook most of my training while riding my bicycle. Over a period of a couple of years, I got to where I am as conscious of my peripheral field as my central field, except that the peripheral field is blurrier. I see the entire panorama in front of me at once.

Moreover, the rod cells, sensitive enough even to form an image under starlight, are only in the peripheral visual field. The fovea, at the center of the visual field, has only the color-discerning and sharp-imaging cone cells, which are far less sensitive,. In very dim light, the center of the visual field becomes a blind spot and, to fill it in, the eyes must dart around like those of a person born without cone cells — as described in Dr. Oliver Sacks’s book The Island of the Colorblind. Walking outdoors on a starlit night in an area with dark sky offers a good lesson about visual abilities.

All ages?

Bicycle industry lobbyists and populist cycling advocates are marketing an “all ages” vision of cycling to the American public. Consider this photo, which appeared in a Streetsblog post promoting “equity”.

Prospect Park West with child on tricycle

Prospect Park West bikeway. Photo copyright Dmitry Gudkov, appears here under fair use rights.

The facility shown is a two-way sidepath alongside Prospect Park, in Brooklyn, New York.

Does “equity” consist of adult bicyclists’ having to take care and slow way down for children on small bicycles with training wheels? We love our children, but on the other hand, the path was not crowded in the photos, and so it doesn’t draw attention to that problem. This is a two-way path, too narrow for safe overtaking in both directions at once.

It could be asked whether it’s fair to ask motorists to slow down because bicyclists are using streets…but then bicyclists using the street may have chosen it to avoid a path crowded with little children, or otherwise not safe at the speed they travel, indirect, doesn’t go where they want to go — not suitable. The right of bicyclists to use the streets is fairly well established in the USA, though with some disturbing limitations, and is of of crucial importance in a this very large country which, unlike the Netherlands, is not table flat over much of its extent, with raised flood barriers between farmers’ fields, ideal for siting pathways.

Here’s another example, from a presentation by Cambridge, Massachusetts bicycle coordinator Cara Seiderman:

Design users, from Cara Seiderman's February, 2009 presentation on cycle tracks

Design users, from Cara Seiderman’s February, 2009 presentation on cycle tracks

Seiderman’s PowerPoint slide conflates several issues. Little children are unpredictable and unsafe, whether on streets or on paths. The elderly woman is likely to be predictable and cautious — she isn’t going to dart out as another cyclist is overtaking. But nobody is wearing a helmet. One of the little girls has a front basket that looks as though it is about to fall off. The elderly lady is wearing black ninja clothing, riding a black bicycle with a black basket.

What does cycling look like when children set the pace? Here is a video showing a school run in a new housing development in Assen, in the Netherlands:

and an older video of the same run:

I suspect that in Dutch cities, as in big cities anywhere, parents are concerned about allowing their children to travel independently. There are other hazards besides traffic hazards: fixed-object hazards, crime, just getting lost. I don’t see children riding on the Amsterdam streets in Andy Cline’s video, linked from his blog here.

The cycling I see in the Assen videos, shot in a new housing development, is similar to how casual and child cyclists ride on crowded shared-use paths in the USA. Small children, and the frequent risk of collision, set the pace at times. The cycling shown is faster than walking but provides not only less exercise per mile, also less exercise per minute!

It would be nice if suburbs in the USA were designed from the ground up so bicyclists and pedestrians had pleasant, direct routes, and children could get around without traveling on busy streets. Some suburbs are: but in most cases we have to build on what we have. I’ve discussed this issue before and made what I think are some practical suggestions.

Is the NACTO Guide a Design Manual?

In cities around the USA, politicians, under pressure from populist bicycling advocates, have pointed to the NACTO (National Association of City Transportation Officials) Urban Street Design Guide and directed their engineering staff to install treatments which it describes.

In case you are going to think of me as a naysayer, I’ll say right here that some of the treatments which the NACTO guide describes deserve attention and inclusion in national design standards — though their presentation in the NACTO Guide typically is flawed, inconsistent and incomplete. (Why these treatments are not included in the standards is a story for another time.)

Other NACTO treatments are so troublesome that they are not widely applicable.

Engineers unfamiliar with bicycling issues may take NACTO designs at face value; other engineers may throw up their hands and comply, faced with the threat of losing their employment. Several engineers who have extensive background and expertise in design for bicycling have resigned, been fired or been demoted when they would not accept the NACTO designs.

What leads to these problems? To put it simply, the NACTO guide isn’t a design manual. It is a smorgasbord of design treatments formatted — right down to digitally-generated loose-leaf binder holes on what are, after all, Web pages — to look like a design manual to politicians and the general public. It was funded by bicycle manufacturers to promote street designs which they expect will lead to greater bicycle sales, and it has been created without the vetting necessary for consistency and accuracy. Its purpose is to generate political pressure to apply the treatments it describes. It is weak on specifics: rife with errors, and with omissions even in describing the treatments it covers.

If I described all of my specific  concerns with the NACTO Guide, I’d be writing a book, so for now let’s just look at a two-page spread of the NACTO Guide. We’ll look at the pages about two-stage turn queuing boxes (2STQBs, for short).

Again, in case you are inclined to think of me  as a naysayer, let me get down to some specifics. I have had information about two-stage turn queuing boxes online for years, I think that they are a useful treatment, and I use two-stage turns: when I realize that I have reached the street where I need to turn left, but hadn’t merged to turn; when traffic is heavy and fast and I haven’t found an opportunity to merge; when ordinary left turns are prohibited. My favorite example is the left turn from Commonwealth Avenue onto the Boston University Bridge in Boston, Massachusetts, where a no-left-turn sign is posted: motorists have to go around a large loop.

Having, I hope, gotten the issue of my opinion of two-stage turns out of the way, let’s consider the spread from the NACTO guide, below.

NACTO pages about two-stage turn box

NACTO pages about two-stage turn queuing box

I have placed that spread online as a PDF file, zoomable to any size you might like. You may click on the link or the image above to get a larger view while reading this text. The PDF will open in a separate browser window or tab. I’ve also posted parts of the NACTO pages in connection with the text below.

Organization and technical language

The NACTO treatment of the two-stage turn queuing box presents issues of organization and of use of technical language.

Problems start with the title of the section. A proper title is not “Design Guidance”, otherwise, every section would be named “Design Guidance”. A proper title is the name of the device, here “Two-Stage Turn Queuing Box”. [And not "Queue" but" Queuing."]

In a proper design manual, the terms “shall”, “should”, “guidance” and “option” go from strong to weak. “Shall” is imperative: for example, a stop sign shall be octagonal. Should, guidance and option statements are increasingly weaker, leaving more room for engineering judgment.

The meaning of technical terms is muddied by jumbling their order and by using them out of context. The terms “Required Features” and “Recommended Features” correspond roughly to “shall and “should” but do not have the explicit, legally-defined meanings of “shall” and “should”.

None of the drawings on the two pages are dimensioned, and no dimensions are given in the text. That is to say, these are not engineering drawings, they are only conceptual drawings. How big are the turn boxes supposed to be? Who knows? Comparing the illustrations reveals that the width of travel lanes differs, but no explanation is given for that. When politicians start beating on the door for NACTO treatments, standards-setting bodies and traffic engineers have to try to put together the pieces. For specific projects, that task often is passed along to hired consultants who make their living by promoting and designing special bicycle facilities. Yes, there is a conflict of interest.

Specific comments

Now, either click on the image of each section of the page below to open it in a separate browser tab, or zoom the PDF to at least 50% size so you can read the text in connection with my specific comments .(You may open it now if you didn’t already.)

Comments on the left-hand page

The left-hand page includes text which may look like design specifications, and drawings which may look like design drawings — to a layperson.

Left half of left-hand page

twostageturn_guidanceLL

Point 1: “An area shall be designated to hold queuing bicyclists and formalize two-stage turn maneuvers.” This is under the heading “Required Features.”  Lacking here is any statement as to where a 2STQB is appropriate, but the “shall” statement here is inappropriate: appropriate shall statements would describe what features are required if one is installed. As of May 2014, the 2STQB is still in experimental status with the Federal Highway Administration — as are all details of its design. A 2STQB is only one way to turn left among others, an option, subject to engineering judgment or specific design warrants. There is neither the room nor the need for a 2STQB at most intersections.

A proper design manual would include guidance about speed and volume of traffic; the additional delay usually required for a two-stage turn; whether bicyclists might take an alternate route entirely; whether use of the box is  mandatory, placing bicyclists who make other types of turns in violation of the law.

Point 4: “In cities that permit right turns on red, a no-turn-on-red sign shall be installed.”

According to the wording here, if the installation is not in a city, the sign is not required.

But also, the shall statement is overly broad, and incomplete. The sign is needed only if right-turning traffic would be in conflict with the bicyclists waiting in the 2STQB: unnecessary in the cross street if traffic turns right before reaching the box or cannot turn right, and unnecessary on the entry street if the cross street is one-way right-to-left. Does the sign belong on the entry street or the cross street, or both? That is not stated. Details, details…

Point 6: The comma makes nonsense of this sentence. Where is the box to be positioned?

The other, subsidiary “should” and “may” statements on this page also are contingent on official approval of the underlying design, and are lacking in detail.

Right half of left-hand page

twostageturn_guidanceLR

Something really leaps out at me here: take a look and see whether it leaps out at you too.

OK, ready? Three of the six illustrations show a line of travel (in blue) for bicyclists straight across an intersection and then illegally and hazardously turning right, directly into the face of approaching traffic in a cross street.

In showing this bizarre routing, the NACTO Guide also fails to address issues with the actual route which bicyclists might take.

Five of the six illustrations show that bicyclists would somehow turn 180 degrees in place. That requires dismounting and is slow and awkward. How would a bicyclist turn when the traffic light is about to change? When other bicyclists are already in the box? How about tandems? Bicycles pulling trailers? Bicycles carrying heavy baggage?

The drawings show a subtly implied but selectively addressed-threat: lanes where motorists travel are shown in a threatening shade of pink — whoops: except in the cross street where bicyclists ride head-on at motorists.

Four of the six illustrations show motor vehicles in right-hook conflict with bicyclists headed for the queuing box. The motor vehicles are turning out of the threatening pink area into what is portrayed as the safe zone– the right-hook zone. In two of the pictures,  vehicles have already impinged on the blue line which represents the path of bicyclists crossing the intersection. Green paint, which has become a catch-all warning of traffic conflicts in bicycle facilities, is shown in the queuing box, it is not shown in the conflict zone. (By way of comparison, Dutch practice in such conflict situations is that the motorist must always yield, and to use “shark teeth” markings to indicate a yield line.)

Two of the drawings show bike lanes in the door zone of parked cars.

The middle left illustration shows a receiving bike lane at the top, out of line with dashed markings in the intersection, so bicyclists bear right just before they cross a crosswalk, potentially colliding with pedestrians who would expect them to continue straight.

All of the illustrations show two-stage turns across two-lane one-way streets, though the two-stage turn queuing box is most useful where a conventional left turn is illegal, unusually difficult or hazardous — for example, when turning from a major, wide arterial street with heavy traffic, or one with trolley tracks in the median.

As already indicated, none of the drawings are dimensioned and no dimensions are given in the text.

Comments on the right-hand page

The right-hand page gives annotated pictures of conceptual installations, with angled views from overhead.

Left half of right-hand page

twostageturn_guidanceRL

The street going from bottom to top in the picture is one-way, as can be inferred by the direction in which vehicles are traveling. That the cross street is two-way may be inferred from the locations of traffic signals and the existence of the queuing box. A real design manual would be explicit about how a treatment would apply, depending on the directions of traffic in the streets.

The end of the traffic island next to the queuing box protrudes so far and is so sharply as to make right turns awkward. No explanation or guidance is given on this issue.

Traffic signals are shown for motor traffic on both streets, but no traffic signal is shown facing the separate bikeway in the street!

Point 3: “Shall” — mandatory — wording differs from that in the same point as made on the opposite page. A real design manual would have a single, consistent statement. “Queue box shall be placed in a protected area.” The queuing box shown here is not protected from right-turning traffic in the cross street. How would that right-turning traffic be managed, or is it permitted at all? Such issues are addressed in a real design manual.

Point 6: “Optional queue box location in line with cross traffic.” The preferred queuing box, then, is not in line with cross traffic. On getting a green light, bicyclists in the queuing box would have to merge left inside the intersection unless there is a receiving bike lane after the intersection, but none is shown. Merging inside an intersection results in hazardous conflicts and is generally illegal. What warrants the choice of one or the other option? It isn’t stated.

Point 8: The illustration shows motorists and a bicyclist inside the intersection, and so they must have a concurrent green light — or, they would if any signal were shown facing the bikeway. Markings guide bicyclists across the intersection, but also into the path of right-turning traffic. The bicyclist and the motorist in the right-hand lane at the bottom of the picture are on a collision course if the motorist turns right.

What is the meaning of the curved markings adjacent to the bicycle parking in the middle of the street? Does the lane with bicycle parking start as a lane with car parking, additionally hiding bicyclists from turning motorists? Or is this an additional lane for motor traffic, discontinued at the intersection, precisely where more lanes are needed to store waiting traffic? Not shown.

Right half of right-hand page

twostageturn_guidanceRR

There is a right-hook threat at both bike lane entries to the intersection.

Bicyclists headed from bottom to top in the bike lane are riding in the door zone of parked cars, and closer to the cars after crossing the intersection.

Point 9: As in the left half of the page, placing the queuing box to the right of the travel lane when there is no receiving lane ahead assures that motorists will overtake bicyclists in the intersection and that bicyclists will have to wait for motor traffic to clear before they can proceed. Motorists waiting to turn right will be stuck behind the bicyclists. Placement out of line with motor traffic is described as the option here, rather than as the preferred treatment as on the left side of the page, and the problem is acknowledged in the caption to this drawing, though no explanation for the different choices is given.

Point 10: A jughandle may be useful if traffic is so heavy or fast that bicyclists have difficulty merging to the normal left-turn position near the center of the street, but then traffic is also so heavy and fast that a signal is usually necessary, not merely to be considered — unless there is already one upstream.

Point 11: Yes, signage may be used, but what signage? A real design manual would show the signs and where they are to be placed.

Point 12: A bicycle signal might be installed, but where? for the entry? For the exit? Its timing?

Point 13: Guide lines, pavement symbols and/or colored pavement. Which? Where? Why?

Had enough?