Author Archives: jsallen

ShelBroCo Magic Green Paint

Here’s a high-tech product which deserves to be used in every new bicycle infrastructure project. The linked page gives a thorough description and videos!

 

An example from one of the videos

An example from one of the videos


Volvo promotes a reflective paint which fades in 10 days!

The last word in safe bicycling, NOT! I mean, this could be a premature April fool’s joke!

The Volvo promotion, also touted on the blog The Verge, is more an exercise in creative photography than anything else, but also does a lot of fearmongering. Buses are shown twice endangering bicyclists to the extent I have to wonder whether the videos were posed. Another video shows a bicyclist smashing into the back of a car, which can be avoided by maintaining safe following distance, not by any lights or reflectorized items. A bicyclist describes a left-hook (in the UK, right-hook in right-side driving countries), a type of crash which is avoided by not overtaking between a vehicle and the kerb (curb).

It is very easy to make reflectorized materials look splendidly bright by using a lamp on or next to the camera. As usual in promotions of nonstandard reflectorized products, a bicycle is shown in the video emblazoned with the product — which only works for the driver of a motor vehicle whose headlamps are aimed at it — but without the headlamp required by law for the bicyclist to alert others. The bicycle’s saddle is at an impossibly uncomfortable angle, and who is to imagine that the chain, tires — and rims — on a bicycle with rim brakes — would be spray-painted? A photo of three bicyclists is clearly doctored: there is no way that one after the other would light up. Same with another where the bicyclist’s clothing flashes on and off while the bicycle remains bright. In any case, reflective coatings are nothing new, but one which is designed to last only 10 days, now that is a new twist in safety products. For information about earlier reflective coating promotions: http://www.bikexprt.com/witness/fabric/index.htm

Another pretty picture from Indianapolis

Here’s another picture from Indianapolis which I discovered online. Its geometry is slightly distorted, as it is from a screen shot. New York Street, in this picture, makes a two-way pair with Michigan Street, which I discussed in my previous post.

You may click on the images to enlarge them and get a clearer look.

New York Street at Arsenal -- proposed treatment

New York Street at Arsenal — proposed treatment

Let’s compare this with the Google Street View on which it is based:

New York at Arsenal Street -- Google Street View

New York at Arsenal N.Arsenal Avenue — Google Street View

I’m not going to discuss this in such detail as in my previous post, but please note:

  • The proposed two-way separated bikeway is no more than 5 feet wide where the two bicyclists are traveling.  (Compare with the bicyclists’ height and the diameter of their wheels, approximately 27 inches.) This bikeway is also between raised curbs and doesn’t even begin to be wide enough for safe two-way travel. It isn’t even wide enough to conform to guidelines for one-way travel.
  • The perspective is odd. The bikeway becomes wider and the travel lanes, already barely wide enough to contain the small cars shown, become narrower in the background.
  • The bikeway is described as “protected” but it crosses several driveways and, astonishingly, it opens into the street in the foreground with bicyclists facing the direction of traffic. What are bicyclists supposed to do here? Riding against traffic is illegal, aside from being highly hazardous. Here’s the view from across the intersection with Arsenal Avenue.
New York Street before Arsenal Street

New York Street before N. Arsenal Avenue

  • Some additional trees have been added in the proposal; smooth pavement has replaced the worn pavement in the Street View,  the cloudy sky has been replaced by a blue sky, and shadows have been added to simulate a sunny day. As in the picture in the earlier post, these changes create an optimistic, appealing effect, but they have nothing to do with the bikeway.
  • And, again, as I asked in the other post, how is this bikeway to be cleared of snow?

New York Street is much narrower than Michigan Street until a couple of blocks east of this point. I don’t see how there could be room for  both a contraflow bike lane and a with-flow bike lane. In my opinion, two-way bicycle traffic is better accommodated on Michigan Street. A route could bypass the narrow section of New York Street by using Vermont Street, a couple of blocks to the north.  That street also has an underpass under Interstate 70 — see Google map. This route would, however, require two-way bicycle traffic on reversing the one-way direction of part of N. Arsenal Avenue.

New York Street connections

New York Street connections

Any bike lane on the narrow section of New York Street ought to be on the left side, on the opposite side from parking: looking up and down the street in Google Street View will show that the present bike lane is in the door zone of parked cars.

Treatments at intersections should favor motorists’ merging into the bike lane before turning, and bicyclists’ overtaking turning motorists on the street side.

PeopleforBikes approves transformation of Michigan Street, Indianapolis with Photoshop

[Note: I’ve changed the title and a few words in this article, because a reader has pointed out the the drawings I’ve commented on, while approved by PeopleforBikes, are not from PeopleforBikes — the impression which an article I cited gave. Nobody has explained as of yet who did the drawings.]

This article critiques a proposed treatment for Michigan Street in Indianapolis, Indiana. Indianapolis is one of four cities which have been targeted for grants by the advocacy organization PeopleforBikes — whose financial support and agenda, let it be clear, and despite its name, are from the bicycle industry.

It’s only fair for me to criticize if I can suggest a better alternative. But first let’s look at existing conditions on Michigan Street

Michigan Street approaching Keystone Street in front of the Thomas Gregg Elementary School is shown in the Google Street View below, from July, 2011.

Michigan at Keystone, Octobrer 2011

Michigan at Keystone, October 2011

Michigan Street presently has a bike lane, visible behind the car in the Street View image. (The car is straddling the bike lane, having given the Google camera car a wide clearance when passing on the right.) The door zone placement of the bike lane creates hazards which reinforce the impression among uninformed people that the government has done the best it could, short of constructing a sidewalk-type bikeway. There are cars parked adjacent to the bike lane in the next block.

Other Street Views show a small number of cars parked on both sides up and down the street. An earlier Street View, from July 2009, shows how the leftmost lane was narrowed and the other lanes were shifted over to make room for the bike lane on the right. You can see the lane lines which were blacked out.

Michigan at Keystone in 2009

Michigan at Keystone in 2009

The left lane was already used for parking before it was narrowed, but now its narrowness, along with the parking, makes it hardly useable for travel.

Taking a larger look at the neighborhood (see Google map) —

Google Map of East Indianapolis

Google Map of East Indianapolis

Michigan Street is half of a one-way pair, with New York Street, a block to the south. These are arterial routes in and out of the city center, which is to the west. Traffic is very light  in Street View images, but it must be heavier during the morning and evening rush hours. The long north-south blocks make wrong-way local bicycle travel on these one-way streets tempting. There is a bike lane on the right, intended for one-way travel.

What, in my opinion, is the best which could be done here to provide for local bicycle travel in both directions?

Let me suggest that making the leftmost lane of each of these streets into a contraflow bikeway would provide for two-way bicycle traffic, with the low stress which would be attractive to novice and casual bicyclists, while maintaining a normal and expected pattern of traffic movements: the streets would be one-way for motorists and two-way for bicyclists.

This would remove parking on one side of the street, but is parking an issue here? Because the blocks are  long from north to south but short from east to west, there are many more available parking spaces on the north-south streets than on Michigan Street and New York Street. The small number of parked vehicles on Michigan Street in the Google Street views suggests that removal of parking on one side of the street would not result in parking overflow. Even for deliveries, the blocks are so short that parking around the corner on a north-south street would not be a much of a hardship.

There is still a concern with this idea, that some bicyclists would ride opposite the flow of traffic in the contraflow bike lane. That issue can be addressed by also having a with-flow bike lane on the left side. Then bicycle traffic adjacent to the motor traffic is traveling in the same direction, and the opposite-direction bicycle traffic is closer to the curb, conforming to the normal traffic pattern and expectations. Here’s an example of this type of treatment, from Fresh Pond Park in Cambridge, Massachusetts:

Two-way bikeway on left side of one-way street

This is a treatment approved for the Manual of Uniform Traffic Control Devices, the national standard reference. In the standards-setting document describing contraflow bicycle lanes, note the wording:

Where used, a contraflow bicycle lane should be marked such that bicyclists in the contraflow lane travel on their right-hand side of the road in accordance with normal rules of the road, with opposing traffic on the left…

A bicycle lane for travel in the same direction as the general purpose lanes may be placed on the left hand side of the general purpose lanes.

Appropriate use of short median strips before intersections could direct motorists to merge into the with-flow bike lane before turning left, but prevent them from merging into the contraflow bike lane, and with minimal impediment to plowing..

There is adequate width on both Michigan Street and New York Street to install this treatment, while still having two through travel lanes, as well as parking and bus stops on the  side without bicycle lanes.

I’m not saying that this treatment is ideal. There are still issues with motorists turning across the bikeway and entering form side streets. However, the normal and expected pattern is maintained, with traffic keeping to the right. The one-way street becomes a two-way street, except that only bicycle traffic may travel in one of the two directions.

It might be desirable to reverse the one-way pattern if more trip endpoints and connecting routes are on the side of the street which would be opposite the bicycle lanes, and to place the morning rush-hour traffic on New York Street to get it away from the elementary school.

Now let’s see what PeopleforBikes is promoting.

Photoshop drawing of proposed Indianaplis bikeway

Photoshop drawing of proposed Indianapolis bikeway

The article which includes the Photoshopped illustration above makes the following statement:

Leaders with the national organization People for Bikes said protected bike lanes are like “sidewalks for bikes” and Indianapolis needs more of them.

It’s hard enough to overcome people’s false sense of security about bicycling on sidewalks without having to fight the bicycle industry’s Astroturf advocacy organization!

The statement, and the soothing but inaccurate term “protected bike lane”, take advantage of the incorrect and often fatal misconception by casual cyclists and parents that sidewalks are safe places for bicycling. Decades of research show that bicycling on sidewalks produces a crash rate higher than on streets, and also show that barrier-separated on-street bikeways are appropriate, preferable and reasonably safe only under a limited range of conditions and with the application of strict design standards which make them very different from sidewalks. In spite of all this, barrier-separated on-street bikeways are by and large the only thing which PeopleforBikes promotes. And here, it’s promoting them by ringing the bell of the public’s fondness for sidewalk cycling.

But, to get down to specifics, how realistic is the PeopleforBikes promotion? To what extent does it reflect applicable and appropriate standards?

Let’s look at the reality factor with the image in general.

Below is a comparison of the Google Street View from October, 2011 with PeopleForBikes’ the Photoshopped image. You may click on it to enlarge it and get a clearer view.

Google Street View of Michigan at Keystone

Google Street View of Michigan at Keystone compared with PeopleforBikes Photoshopped image

The school building at the right side is identical, but the other elements of the original image have been enlarged to shift them forward: the traffic signal and utility pole,  buildings on both sides of the street, even the clouds in the sky. The burned-out building on the left is now out of the picture. The worn pavement and faded lane lines of the street have been replaced with a smooth, clean, constant color.

The original Street View shows a blighted neighborhood, heartbreak of the American heartland. and if you open up Street View and look around, you’ll see a number of buildings with boarded-up windows. In the Photoshopped image, the neighborhood is nicely spruced up.

Changing the ambiance creates an air of optimism and helps to sell the bikeway, but on the other hand, the Photoshopped realignment of the streetscape makes this into a fantasy image, not a depiction of any possible future reality.

Now let’s examine the street layout.

PeopleforBikes The artist has placed the street segment which goes off to the left outside the Photoshopped image. The crosswalk in the foreground appears to be in mid-block, unless you notice the traffic signal  mysteriously hanging in a tree at the right, its supporting post  outside the picture.

Another look at the PeopleforBikes image

Another look at the PeopleforBikes image

The image below is a composite, with a part of the Photoshopped image (area with darker pavement) pasted over the unaltered one, and showing the changes in lane widths. The car at the right is the real one from the unaltered image, and the more distant car is Photoshopped. PeopleforBikes The artist has made all of the travel lanes as narrow as the leftmost one. Again, you may click on the image to enlarge it and view it more clearly.

A comparison where the enlarged parts of the image are matched

A comparison where the enlarged parts of the image are matched

The next comparison reveals some issues with dimensioning. I have brought the image of the car in the Photoshopped drawing forward and enlarged it in proportion to the lane width to compare it with the real car. The Photoshopped car is way too big. Also, I have drawn a red line extending forward from the curb line in the next block. That curb line leaves too little width for the right-hand lane — already very narrow — to continue. Assuming that the travel lane in the Street View image is the usual 12 feet wide, PeopleforBikes The artist has reduced it to approximately 9 feet in the nearest block and to 4 feet in the next block — but without any indication that drivers must merge. Because the left lane is used for parking, then only one lane remains usable for through travel.

Comparison of car sizes

Comparison of car sizes

Next, let’s look at the width of the bike lane and proposed separate bikeway.

The near-horizontal red line in the image below extends from one side of the street to the other along the edge of a crosswalk. The other red lines which cross it define the boundaries of travel lanes, a traffic island, the bikeway and the right-hand sidewalk.

Comparison of widths

Comparing widths

If we assume that the right-hand and middle travel lanes in the unaltered image are the typical 12 feet wide and the sidewalk is 5 feet wide, then the two-way bikeway is also about 5 feet wide. This is very tight even for a one-way bikeway. The minimum for a two-way bikeway according to AASHTO [American Association of State Highway and Tranportation Engineers] guidelines 10 feet, preferably with rideable shoulders, and 12 feet are recommended. A 5-foot-wide bikeway between the curb at the sidewalk on one side and a traffic island at the other guarantees congestion, head-on crashes and diversion falls at curbs. Small children and novice cyclists, especially, don’t have the skill or judgment to ride safely under such tight conditions.

But in addition, it might be asked what is the purpose of the 8-foot-wide traffic islands (wider yet in the next block), when the bikeway next to them is only 5 feet wide — and why a two-way bikeway has been placed on the right side — which is the wrong side — of a one-way street.

Finally, let’s look at the only street intersection visible in the Photoshopped image. It is in the deep background. The image below is blurry because it has been enlarged.

intersection in background of picture

intersection in background of picture

Motorists turning right from Michigan Street must cross the bikeway, looking both right and left, and backing up traffic, and then also yielding to traffic on the sidewalk, likely blocking the bikeway. Motorists entering Michigan street must yield first to sidewalk traffic, then to traffic on the bikeway, blocking the sidewalk, and then to motor traffic, blocking the bikeway and possibly also the sidewalk. The white building on the corner hides motorists and bicyclists approaching from the right from each other — already the most hazardous conflict. The  proposed solution to this problem is to paint the pavement in the conflict zone green.

In my proposal with bike lanes on the other side of the street, motorists would block the sidewalk when waiting but would cross both the contraflow and with-flow bike lanes in one move, as is usual when making left turns.

And, I might ask, how would this complicated layout be cleared of snow in winter?

Let me summarize: PeopleforBikes has created put its stamp of approval on a pretty picture which  doesn’t reflect anything real or workable,. This production amounts to a shameless propaganda effort reminiscent of old Soviet publications where images were altered to airbrush out people who had fallen out of favor. The design-by-Photoshop effort shows a profound lack of understanding of, or concern for, issues as fundamental as the necessary width of a general-purpose travel lane, or of a bikeway, or the hazards of wrong-way riding.

Is this an electrically-assisted bicycle?

Elf microcars, from Organic Transit Web site

Elf microcars, from Organic Transit Web site

The photo above is of ELF microcars from the US company Organic Transit.

The ELF is marketed as a velocar — an enclosed, pedal-powered vehicle — but in reality, it is an electrically-powered microcar designed to meet the legal definition of an electrically-assisted bicycle (or tricycle) — like a moped, by having vestigial pedals — and so to be street legal without meeting the requirements for equipment, registration and  driver licensing with a motor vehicle. The microcar is a viable concept, but whether microcars will succeed in the USA, or this one will succeed, is open to question. I do expect that the diversity of vehicle types will increase with time, as I’ve stated in an earlier post on this blog.

Most of the ELF’s power is from the electric motor. It can carry two or three people, or one person an a substantial amount of baggage, but only the one person in front has pedals. There is only a 3-speed geared hub for the pedaler, though a vehicle this heavy needs wide-range gearing if pedal-powered — so, again, the pedaling is secondary to the electric power.

The ELF can charge its battery from the power grid, or more slowly from sunlight, if there is sunlight. Claim is that the ELF travels as fast as most city traffic, but the top speed (limited by proposed electric-bicycle laws) is 20 mph. Legal to use on bike lanes or bike paths? Subject to mandatory bike lane laws? Open to question but it wouldn’t fit them very well — there are problems with microcars for disabled people on Amsterdam bikeways, as illustrated in a previous post. This type of vehicle gets used on bikeways, whether it is legal or not.

Claim “is much safer than a bicycle” is unsubstantiated, as the ELF hasn’t been around long enough to establish a safety record. Three-wheel vehicles, unless very low-slung, are tippy, and the people in the promo pictures are wearing neither seat belts nor helmets.

When slow is too fast

The basic speed limit, not to go too fast under the existing conditions, is often lower than the posted speed limit.

When facilities like the bike lane in the video are built in which 10 mph, or even 5 mph, is excessive speed, and, worse, when we are required by law to use them, then we get clobbered three ways. If we ride at safe speeds, the utility of bicycling for transportation and exercise is greatly reduced. If we ride faster than is safe, then we may crash, and be held at fault. If we avoid the facilities, we may be cited for not staying in our place, and harassed. And this, when bicyclists rarely can ride at the posted speed limit.

I’ll also quote my friend Mighk Wilson’s comments about the video:

It’s important to differentiate between “fault,” which is a legal matter for our purposes here, and “contributing causes.” If we only address fault we will usually fail to prevent crashes…

So who contributed to your crash? Obviously the motorist…he’s 100% legally at fault. But the designer of the bike lane also contributed, by leading you into blind spots where you’d be in conflict with turning vehicles. You yourself contributed by traveling at a speed at which you were unable to see, react and brake for the turning vehicle. Our bicycle advocacy groups contributed by insisting that bicyclists should always get to pass stopped motor traffic even when it’s risky to do so. Our land use planners contributed by allowing commercial driveways so close to major intersections. I could go on…

Part of the problem here is not only that the bike lane leads to blind conflicts, as Mighk points out, but also that it leads to false expectations of what is safe. I’d also add that planners, and lots of other people, contributed to causation of the crash by generating patterns of land use and mode choice which lead to traffic congestion. It is ironic that while it was only safe to travel at low speed in the bike lane, the traffic in the travel lane was stop-and-go, and had stopped completely. Whether a cyclist would have been able to travel safely at a higher average speed without a bike lane is open to question.

Lessons of Taiwan crash

The video embedded below of a car-bicycle collision in Taipei, Taiwan has been making the rounds on the Internet. When you have started the video playing,you can click on “Youtube”, and then on the little gear wheel at the lower right of the image to boost the resolution to 720 lines for the clearest view. Have a look, and then let’s discuss the lessons which this crash might hold.

First, let’s get some things out of the way. Where this video was posted  — by a Taiwanese media outletand in several other places — search on “Taiwan bicycle crash in crosswalk” and you’ll find them — there has been some wonderment that the cyclist on her bike-share bicycle landed on her feet. There have even been comments that the video  is faked. Well, it isn’t: if you look at it frame by frame, all the motion is continuous. There have been many comments about how nobody went to help the cyclist, and particularly about the callousness of the driver who checked his taxi after the bicycle glanced off it, but did not go to the aid of the cyclist. He does not come off well.

There have been recriminations against the driver whose car struck the cyclist — not deserved, as the cyclist was crossing against the light and concealed by stopped traffic. The driver swerved in an attempt to avoid her, probably saving her  from serious injury. The driver also stopped following the crash, but  the car is mostly out of the picture and the video cuts off too soon to show the follow-up.

There have also been many comments about how cyclists should not ride in crosswalks. I agree, if the crosswalks are alongside streets, but  in this case the crosswalk does not connect to sidewalks at a street intersection. Rather, it connects a path in a separate right of way where there are no turning movements by motorists. This crossing was properly signalized, too.

I think that the stopped, congested traffic misled the cyclist into thinking that  she could cross safely against the signal. Note the moving opposite-direction traffic at the far left of the picture: the street is a boulevard with a median. All the opposite-direction traffic should be on the other side of the median…but the roadway on this side of the median oddly has one lane for opposite-direction traffic — oops!

I see failure to obey traffic rules here, and not only by the cyclist: the  driver of the yellow taxi blows through a red light to cross the crosswalk, and the one whose  dashcam recorded the crash starts up on the red light while a pedestrian is starting to cross on a walk signal. The video ends before we see whether e dashcam motorist is going to stop, but it doesn’t look that way.

The cyclist puts a foot to the ground just before the car strikes her. That may have contributed to her remarkably ending up on her feet, but it isn’t a sign of good bike handling.

I expect to be accused of blaming the victim for posting these comments. That misses the point of this post, which is to offer some food for thought about how to avoid crashes. Obeying traffic signals is one of the lessons here, and another is not to ride blindly into a gap where there might be cross traffic.

I certainly hope that the cyclist did not suffer any serious injury, but I do see her as mostly at  fault for the crash. She is the victim, or to put it better, the vulnerable road user, in that she is the only person likely to have been injured in this crash, but she crossed against the light. What’s more to say, except that the opposite-direction lane created a trap which she evidently did not anticipate.

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 even been 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.