About bicycle lighting and onions

Posted on November 15, 2010 by jsallen

A chance meeting can lead to unexpected discoveries.

I met and spoke with Kurt Cibulski following a reading from a new book by its author, a mutual friend. I had arrived at the reading by bicycle; Kurt and I were talking bicycling. Kurt explained that he has a seizure disorder. The bright, rapidly-flashing LED headlights that bicyclists are increasingly using can initiate a seizure for him. “Who’d ‘a’ thunk it.” thought I.

Who? A proper, national standards-setting body, because someone, somewhere, would have brought the issue to its attention. On second thought, it’s obvious. Flashing lights are well-known to trigger seizures.

It’s also a truism that flashing lights draw attention. Many bicyclists ride in urban areas with overhead lighting, and don’t need a steady headlight beam to guide their way. But on the other hand…there’s the seizure problem.

Without careful standards setting, issues like this slip through the cracks. Designs get based on whim, commercial appeal, economies of production and avoidance of liability risk.

In the USA, individual cyclists are held responsible under state laws for using lights at night, but law enforcement is near-nonexistent, and many cyclists don’t use lights. The USA does have a Consumer Product Safety Commission, which, under pressure from the bicycle industry, has set standards — weak standards — only for retroreflectors on bicycles, never for lights. Retroreflectors only work for drivers whose headlights are pointed at them, and do not light up for the pedestrian stepping off the curb, the motorist in the cross street ahead, two bicyclists on a path approaching each other head-on. Bicycle manufacturers can point to Federal regulations and say that they are doing something for nighttime safety, while not being held responsible for these deficiencies.

This situation holds some ironies and unintended consequences beyond the obvious one that cyclists are being injured and killed for want of lights. The lack of standardization in the USA has given lighting manufacturers free rein to innovate, and has led to the availability of some very fine bicycle lighting systems. In the USA, when you see a cyclist with a light, you will probably see that cyclist from a good, long distance, because the light is a very good light.

In Germany, by way of contrast, lights are required on new bicycles. Manufacturer pressure comes to bear in a different way. To keep expense down, most lights only meet the letter of the law and are are less bright, and much less reliable, than the good ones sold in the USA. Bureaucratic inertia has compounded the problem: Germany requires bicycle lights to be powered by a generator. That made sense 40 years ago when battery lights were weak and battery replacement was expensive. Today’s efficient light-emitting diodes and high-capacity rechargeable batteries make battery lights economical and practical.

Generator lights also have improved, thanks to advances in technology and to discerning European cyclists’ demand for better lights that also meet the requirements of their laws — but a good generator lighting system can cost half as much as the bicycle on which it is installed.

A restrictive legal climate leads to this kind of market distortion; contrast this with the wider scope of innovation and slip-through-the-cracks issues in the US market.

I can’t help noticing that kiosk “bike share” (actually rental) bicycles that are becoming popular in American cities all are equipped with LED headlights and taillights, powered by a generator in the front hub. It only makes sense. The rental agencies have a more direct liability exposure than bicycle manufacturers who sell to individuals. But — the lights on the rental bicycles flash, because the generators produce alternating current and the output is not smoothed. Possibly also because flashing lights are popular and nobody though of the seizure-disorder issue.

Where are we heading with all this? I think that we’re approaching a political tipping point where regulations requiring lights on at least some kinds of new bicycles might be possible in the USA: both because of an increase in interest in utility cycling, and because improving technology had made bicycle lights much less expensive, more reliable and more compact. I mean, if little children can have flashing LEDs in the soles of their shoes, just to look cool, it isn’t much of a leap to think that every new utility bicycle could be equipped with lights.

But we also need to be smart, and look forward as technology improves, so regulations don’t box us in with outdated technology and inferior products, as in Germany.

Now, about those onions:

To give Kurt proper credit in this article, I asked his name and came up with another unexpected discovery. He spelled his name, and then volunteered, “Cibulski means ‘onion man’ in Polish. It’s a pan-European word.” Yes! Again, who’d ‘a’ thunk it? German, Zwiebel. Spanish, cibolla. I looked it up, and found variants in languages as diverse as Basque, Czech, Gaelic, Norwegian, Romanian…

I suppose that there’s another parallel, besides the two unexpected discoveries. Bicycle lighting issues, with all the political and technological complications, peel apart in layers like an onion, too.

Thanks, Kurt!

Posted in Bicycling, Equipment, Laws, lighting | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 11 Comments

Davis Planners and Advocates Opine on Sidepaths

Posted on November 7, 2010 by jsallen

This post supplements my previous post linking to documents about Davis bicycle facilities. Please bear in mind that Davis was the first community to introduce bike lanes in the USA, and that its bicycle program strongly favors conventional bike lanes, which are separated from the adjacent lane only by a painted stripe. I have found that the Davis documents uniformly and strongly recommend against bike lanes behind barriers or parked cars. Not only that, the recent warnings are more definite than the early ones. Some quotes, starting with the most recent and working backwards in time:

Theodore Buehler, Fifty years of bicycle policy in Davis, CA (Master’s thesis, 2007). See pages 50 ff., “Lane location relative to motorized traffic”.

The early experiments included three different types of bike facilities (see examples at the top of this section):

  1. bike lanes between car lanes and the parking lane (Third St.),
  2. bike lanes between the parking lane and the curb (Sycamore Lane), and
  3. bike paths adjacent to the street, between the curb and the sidewalk (Villanova Ave.).

The first bike lanes included all of these types, to test them in real life to see how effective they were. The on-road lanes worked best, the behind-parking lanes were the worst, and the adjacent paths were found to work in certain circumstances. This is an example of the wide level of experimentation that occurred during this period. Had the city tried to do extensive research without construction, it might have settled on an inferior design. And not having tried all three designs, it might not have recognized it as inferior, and the entire experiment could have been declared a failure.

Dale Lott (one of the early advocates for special bicycle facilities in Davis, who also conducted research as to their safety and effectiveness), “How Our Bike Lanes Were Born“, op-ed piece which appeared in the Davis Enterprise in 2003:

We insisted on some experiments that turned out well and some that were flops.

One flop was on the first block of Sycamore north of Fifth where we put bike lanes next to the curb with parking next to the auto travel lane. It looked great on paper, but was a mess on pavement. When cars turned into the University Mall driveway, they crossed the bike lane. Both driver and rider, whose view of each other had been obscured by the parked cars, had an emergency situation.

David Takemoto-Weerts (University of California, Davis Bicycle Coordinator, A Bicycle-Friendly Community, the Davis Model (conference presentation, 1998)

Because Davis pioneered the bike lane and other bicycle facilities in this country, it is not surprising that some “experiments” were less successful than others. One such example was the construction of “protected” bike lanes where motor vehicle and bicycle traffic was separated by a raised “buffer” or curbing. In some cases, the bike lane was established between the parking shoulder and the curb line (i.e. cars were parked on the left of the bike traffic lane). Needless to say, any “benefits” of such facilities were soon found to be outweighed by the many hazards created for their users.

Most such well-intentioned, but ill-fated designs were phased out long ago. However, some facility design decisions made decades ago were not so easy to remedy. The most pervasive example in Davis is the two-way bike path immediately adjacent to a roadway. Particularly problematic are single two-way paths located on only one side of the adjacent road. The problems associated with these designs have been described in any number of publications, and they are well illustrated at several locations in Davis. In spite of this documentation, some residents, city officials, and developers remain quite vocal in advocating such facilities when new construction is being planned and designed. The city and campus have attempted a variety of mitigation strategies to reduce the hazards or inefficiencies associated with these side paths, but many observers believe that continuing to build such facilities is wasteful at best.

Deleuw, Cather and Company.: Davis Bicycle Circulation and Safety Study. 1972 (excerpt — for complete document in three parts, see table of contents page.

Protected lanes

…Protected lanes located between the parking shoulder and curb line have most positive separation. However, the parked cars create sight distance problems at driveways and intersections. Inability to cross streets in midblock in this type of treatment results in two-way usege which, in turn, leads to intersection problems described subsequently…

Sidewalk and Independent paths

Sidewalk pathways eliminate midblock bike-motor vehicle friction. However, frictional interference of pedestrians may discourage usage of these facilities as does frequent interruption by cross streets and driveways or meandering of the path. An additional problem is establishment of a visual relationship between motor vehicles on the sidewalk path on approaches to intersections…

Posted in Bicycling, Bike lanes, Crashes, Cycle tracks, Sidepaths | Tagged , , , , , , , , , , , , , , , | 4 Comments

Davis, California historical documents

Posted on November 7, 2010 by jsallen

Thanks to John Ciccarelli, Robert Sommer and David Takemoto-Weerts — and David’s students — among others — I am able to post online a number of documents about bicycling in Davis, California and the Davis bicycle program. Davis has the longest experience with a bicycle program of any city in the USA, and a large population of cyclists thanks to its being the home of the University of California at Davis.

You may surf to my table of contents page for the Davis documents and a complete list of people I have to thank — but also please read the rest of this post:

Of particular note are the conclusions which Davis has reached about different types of bicycle facility designs. Davis pioneered some brilliant design innovations, for example, bicycle traffic circles. On that topic, also see these videos:

Davis also has been willing to learn from mistakes and move onward. In another post, I have assembled quotes about Davis’s experience with barrier-separated bike lanes, versus conventional bike lanes separated from the adjacent lane only by a painted stripe, an issue which is particularly relevant as I write this in 2010.

Posted in Bicycling, Roundabouts | Tagged , , , , , , , , , , , , | 2 Comments

Green Wave, Checkered Flag?

Posted on October 29, 2010 by jsallen
Vendor's cart in Union Square, New York City bike lane

I am writing this post in response to comments by Mighk Wilson and Khalil Spencer on another post on this blog. They discussed the difficulty of cycling in a city with synchronized traffic signals (a “green wave”) set to a higher speed than cyclists can manage, and the potential of a slower green wave to make a street more attractive for cycling. I’d like to take a more general  look at the green wave and how it affects traffic.

My understanding of the green wave is based mostly on experience. (And so, anyone who can provide more details based on theory, or can correct me, please do…)

In my high-school years, I lived and learned to drive in Baltimore, Maryland, USA, one of the first cities to implement traffic signal synchronization. I have also lived, driven and cycled in Manhattan, where most traffic lights are timed to create green waves.

A green wave can only work under a limited set of conditions. If these do not apply, then despite best efforts to time traffic lights for the smoothest possible traffic flow, a signal sequence can still appear random. Drivers have no clear strategy for avoiding red lights beyond speeding up when the next light is still green. On the other hand, when a green wave is working smoothly, drivers may feel as if a green-wave Tinkerbell is darting along overhead and pointing her magic wand at every traffic light to turn it green.

Traffic engineers use clever math so a green wave, surprisingly, can be applied to streets heading in more than one direction the same time — though it works better if they are one-way. Heading north on Charles Street from church in downtown Baltimore, my family would get green lights for block after block, except at the few two-way streets, where all bets were off. Then as we headed into the more random street pattern at the north end of the city, we just had to take each traffic light as it was. On the other hand, traffic lights were less frequent in this less densely built-up area.

My experience was similar in Manhattan. The green wave worked smoothly on one-way streets and avenues, but  when crossing two-way ones, and when driving on them, it didn’t. This obvious difference gives drivers a strong incentive to use one-way streets and avenues for through travel, where possible.

Advocates of the sort who would view streets as a neighborhood resource often protest conversions of two-way streets to one-way, see for example this call to action. Traffic engineers who are concerned with the effect on congestion and crash rates have the opposite opinion — see, for example, this presentation. (I expect that the choice is not quite so stark as these two examples make it — as usual, such decisions must be made on a case-by-case basis.)

A green wave works smoothly only when there are no stop signs on a green wave street, though stop signs can be used on cross streets.  Double-parked vehicles, vehicles that have entered the street and are waiting for a light to change, vehicles — including bicycles — that can’t keep up with the pace set by the signals — anything that slows traffic down or reduces the number of lanes available increases the likelihood of not keeping up with the pace set by the lights.

A green wave often encourages travel faster than the pace set by the signals. That’s because there is an advantage in racing to the front of a platoon — where each signal has just changed to green — when preparing a turn — then after turning, racing to the end of the block so as to catch the end of the green there. A driver may speed through another few blocks to get to the front of the platoon before turning again. The advantage of this tactic is quickly obvious: After turning the corner at the head of a green wave onto another green wave street, a driver will be facing a signal at the next intersection which is about to turn yellow, then red.

The typical 30-mile per hour speed limit in grid cities like Manhattan often leads to motorists’ speeds considerably in excess of that limit, and to more unpleasant conditions for bicyclists.

On the other hand, synchronizing signals to a speed more comfortable for bicycling will discourage use of a street for through motor-vehicle travel, making it more attractive for bicycling. I have ridden on a street in Saint Petersburg, Florida, with the signals synchronized to 15 miles per hour, and it achieved that goal quite well. It would have worked better if it had been one-way — it ran up a moderate slope from the waterfront, and for most bicyclists, 15 miles per hour was hard to maintain. Downhill, on the other hand, the speed setting could have been 20 miles per hour without creating difficulties for bicyclists.

Bear in mind, though, that comfortable level-ground travel speeds for bicyclists cover a 3 to 1 range , from about 25 miles per hour down to 8 miles per hour — not nearly as uniform as for motorists, even considering the issues with motorists’ speed already mentioned. A predictable increase in the volume of electrically-assisted bicycles and motor scooters will complicate the issue of speed setting even further. The advantage of a slow green wave, given these issues, is not so much to allow bicyclists to travel farther before facing a red light as to discourage use of the street for through travel by motorists.

Posted in Bicycling, New York City, Sidepaths, Traffic Signals | Tagged , , , , , , , , , , , , , , , , , , | 1 Comment

I approve of this?

Posted on October 29, 2010 by jsallen

UPDATE: This post gives background information on the intersection. I have now ridden through it, and my opinion of it has changed. I have another post about it, and a video. Please check them out.

The image below shows a special installation of traffic signals and markings at the intersection of 16th street, U Street and New Hampshire Avenue NW in Washington, DC. To enlarge the image so you can read the text descriptions, click on it. You also may have a look at a Google map satellite view. Then please return to this page for my comments.

16th Street, U Street and New Hampshire Avenue NW, Washington, DC

Pierre L’Enfant and Andrew Ellicott — and let’s also not forget African-American surveyor Benjamin Banneker — laid out Washington’s streets from scratch —  in the pre-automotive 1790s. Washington’s diagonal avenues give it an openness and unique sense of place — but the resulting uneven-length blocks and multi-way intersections make for some serious headaches now. Some traffic movements are odd, traffic signals can not be synchronized efficiently…

Before the new installation, no signals in this intersection faced new Hampshire Avenue. Bicyclists would sometimes use New Hampshire Avenue for through travel, though its conflicting one-way segments made that illegal and there was no conflict-free crossing interval.

The illustration above is from a page posted by the government of the District of Columbia describing a new installation of contraflow bicycle lanes, bicycle waiting boxes and special traffic signals. At first glance, these may raise the hair on the back of the necks of people who are suspicious of special bicycle facilities treatments.

Look again. The bike boxes look odd only because they connect with diagonal New Hampshire Avenue. They are cross-street bike boxes — which bicyclists enter from the left. Bicyclists from New Hampshire Avenue enter on a separate signal phase from the motor traffic on 16th Street, rather than to creep up on the right side of motor vehicles, as with more-usual bike-box installations. Motorists do not have to crane their necks or stare into a right-side mirror looking for these bicyclists.

The cross-street bike boxes are even more conflict-free than usual. Because only bicycle traffic runs contraflow, bicyclists do not have to negotiate with any right-turning traffic when entering the intersection.

To summarize: this installation, importantly, does not violate the fundamental traffic-engineering principle of destination positioning at intersections, as so many special bicycle facilities installations do.

Or, looking at the same conclusion from a different point of view, the installation does not require or encourage bicyclists to do anything dangerous or stupid, and it offers reasonable travel efficiency considering the situation it addresses.

I am not going to say that this installation is perfect. I can see the following issues.

  • Bicyclists’ having to wait through two traffic-signal phases is inconvenient and might lead to scofflaw behavior. A “scramble phase” could allow crossing in one step and might even apply to bicyclists arriving from other directions. It would reduce the time allocated to for all the other phases, but it might be practical, and preferable, at times of low traffic. Signals and markings which only apply at some times could, however, be confusing.
  • The installation addresses only bicycle traffic entering the intersection from New Hampshire Avenue. Traffic control remains as it was for 16th street and U street. Considering the many ways in which bicycle travel could be made slower and/or more hazardous in the name of making it better, this may be a case of “best leave well enough alone,”  but on the other hand, real improvements might be possible.
  • The bike boxes on 16th street could be interpreted as encouraging bicyclists on that street to overtake motorists on the right, then swerve in front of them, as is the more conventional with bike boxes.
  • Just outside the lower left of the picture on New Hampshire Avenue, there is wrong-way parallel parking next to the bike lane. Motorists exiting wrong-way parking spaces are in head-on conflict with bicyclists, but cannot see them if another vehicle is parked ahead. (See illustrated description of wrong-way parallel parking elsewhere, if the explanation here is unclear.) At the top right, on the other hand, note that the bike lane is farther from the curb: this segment of New Hampshire Avenue has back-in right-angle parking, avoiding the sight-line problem.
  • And, while we’re at it, I have another issue with the street grid, though it’s common to many other cities and not readily subject to correction. Streets that go east and west guarantee that twice per year,  for several days, the Sun will rise and set directly along the streets, glaring into drivers’ eyes.  If the street grid ran northeast to southwest and northwest to southeast, this would never happen. All you Pierre L’Enfants of today designing new cities, please take notice, here’s your chance to acquire a reputation as Pierre L’Enfant Terrible!

This installation is the subject of experimentation sanctioned by the U.S. Federal Highway Administration, with observation, data recording and analysis to see how it works in practice. The experimentation may turn up more issues, or reveal that some are of little importance.

Now, dear readers, you also may also have points to add to the discussion. Let the comments fly.

See also: GreaterGreaterWashington blog entry about this installation; Washington, DC Department of Transportation page about it; Google maps satellite view.

Posted in Bicycle facilities, Bicycling, Bike box, contraflow | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 10 Comments

Guest posting by John Schubert: New York, City of Confrontation

Posted on October 28, 2010 by jsallen

Responding to an article in the New York Times, [archived] a correspondent asked John Schubert

Why isn’t NYC concerned about being sued because of lousy bike-lane-
design-caused wrecks?

and he replied:

Good question. I think it’s important to know the answer from NYC’s point of view. I’m not their spokesman, but I’ll try.

First of all, they get sued no matter what they do. It’s a city of confrontation.

Second, NYC knows it will always have collisions, injuries and deaths. They would not view any one street design as a perfect protection against these problems, nor against litigation.

Third, they are SO bombarded with aggressive drivers, nonmotorized road users wanting some sort of relief from aggressive drivers, and the usual paint and path propaganda, that they buy into the idea that separation is necessary in NYC, even if not elsewhere, because NYC is unique.

I believe NYC does have a civility problem. Separated bicycle facilities don’t solve that problem, but in the minds of true believers, at least they avoid that problem. I think you can’t have a livable community without addressing THAT problem.

NYC does have other unique concerns. I suspect the biggest is the huge volume of midblock car stops, more than anywhere else, mostly because of taxis getting and discharging passengers. I think the designs they use to answer this are silly, but the ‘vehicular cyclist’ alternative hasn’t been made appealing to them. Yet.

Posted in Bicycle facilities, Bicycling, Cycle tracks, New York City, Sidepaths, Sidepaths | Tagged , , , , , , , , , , , , | 8 Comments

Deer dears

Posted on October 28, 2010 by jsallen

OK, the title “Deer Dears” might seem a bit obscure. It refers to children walking and bicycling in urban areas.

Teachers leading a queue of young chilren across a street, holding on to a long ribbon

I chose the title because I’m  recalling a Bicycling Magazine opinion piece which my friend, long time Philadelphia bicycling advocate John Dowlin, wrote some thirty years ago. The title was “Cyclists as Urban Deer”.

Dowlin’s premise was that cyclists in urban areas, like deer in rural areas, are vulnerable, and deserve special attention and caution. He went on to make the point that the presence of cyclists is a measure of the health of urban transportation.

I wrote a response to Dowlin’s article, and it was published too. I suggested that cyclists do better to be smart like the fox. To put it in the simplest possible way: deer stampede out of the woods; foxes look before they cross the road.

The analogy still holds, I think, and it is more compelling now given the current widespread campaign for the construction of bicycle sidepaths which reduce foxy cyclists to deer, appearing from concealment behind parked cars and crowds of pedestrians — and, which also keep newbie cyclists in a state of arrested development, expecting everyone except themselves to look out for their safety.

Certainly, on the other hand, children aren’t ready yet to look out for themselves. We must, then, ask a few questions:

  • To what degree is it actually possible to protect children from traffic hazards?
  • Do we actually protect them from traffic hazards, or only create an illusion of safety?
  • To what extent do other hazards — that a child might get lost, or ride off the top of a flight of stairs, or become a victim of crime — commonly bullying, bicycle theft — limit the child’s travel options? (Stranger abduction is the bugaboo, I know, though it is rare.)
  • What sacrifices in safety and efficiency of travel for other road users — including cyclists and pedestrians — are we willing to make so children can travel independently?

My own opinion is that these issues can generally be resolved to a satisfactory degree for child cyclists on quiet residential streets and on paths that cross roads infrequently, but not on urban arterials or on paths built alongside them.

Now, in answer to a common rejoinder: I’m entirely sympathetic with the point made these days about children’s not walking or bicycling as much as the older generation — my generation — did. I recall my own suburban childhood, in which I walked to school, or I walked a mile to and from the nearest school bus stop. But I’m not going to be nostalgic about that, either. I was bullied at a couple of bus stops, day after day, and at only one of them did I manage to stop the bullying, when accumulated rage overcame caution and I punched the bully in the mouth.

I rode my bicycle in my quiet suburban neighborhood, starting at age 7, but my parents didn’t allow me full freedom to travel on my own, either on foot or by bicycle, until my teen years — appropriately so. I have done the same for my own son.

I’ll put out another thought about stranger abduction, while I’m at it: the grand emphasis in much design of bicycle facilities these days is on perceived safety, often in opposition to actual safety. Now, if we similarly tried to design our cities to create the perception of safety from stranger abduction, what would they look like?

To sum up: the utopian dream expressed by, for example, former Bogotá mayor Enrique Peñalosa, that young children should be able to travel independently everywhere in an urban area, remains just that, a utopian dream, and let’s acknowledge that. Young children are dear to us, and they are too much like deer, too little like the fox, to set out on their own everywhere in cities.

Posted in Bicycle facilities, Bicycling, Bike lanes, Crashes, Cycle tracks | Tagged , , , , , , , , , , , , , | 1 Comment

Turn out the lights?

Posted on October 22, 2010 by jsallen

My attention has been drawn to a video from the U.K. that advocates removal of traffic signals.

I am sure that removing traffic signals is sometimes beneficial — my late friend Gihon Jordan pioneered it in Philadelphia, and he was able to report reductions in crashes. He did a careful survey of crash data to confirm that result.

On the other hand, in many situations, removing signals will not improve safety and mobility, or it must be accompanied by other changes (such as conversion of intersections to roundabouts) if it is to work.

My point in writing this, though, is not to try to evaluate the practice, or the particular intersection shown. Rather, I want to point to a style of advocacy. The video shows some heavily-edited clips of congested traffic before the signals were removed — and free-flowing traffic after, but the video consists mostly of a series of testimonials. There is only one statement by an engineer who might have the technical background to evaluate where traffic-light removal might be suitable. The remaining statements are by ordinary citizens with no particular technical expertise, including two groups of schoolchildren. The video casts the traffic-signal industry as an evildoer by implying that it is unduly influencing design choices, a statement which the video does not support with any evidence. There is some narration to the effect that accompanying measures are needed, but this is given way too little time to explain such issues adequately. Only one negative opinion is represented, from a blind man who, understandably, has more trouble with uncontrolled intersections than with signalized ones.

Traffic engineering has been subject to political pressure as long as it has existed, and with very mixed results. To be sure, we wouldn’t have infrastructure for travel if the public didn’t agree to fund it, but then, there is a strong element of tragedy of the commons in the uneconomical use of clean air and of subsidized infrastructure. Dominant modes of transportation — railroads in the 19th century; private motor vehicles and commercial air travel in the early 21st, — distort transportation choices — by making streets less hospitable, by taking the lion’s share of public funding, by reducing demand for other modes so they become less economical, by affecting patterns of land use. A full-cost, pay-as-you-go model would not be practical, because so much infrastructure must be held as a public monopoly: there can be only one set of streets, one urban public transportation system, etc. and it must be accessible to people at all income levels.

While political pressure is unavoidable, appealing to the general public for implementation of a specific measure has its perils. Where infrastructure choices are driven by such advocacy, the results often are out of tune with best practices as established by careful analysis. Common examples are demands for more traffic lights or stop signs — or, getting around to the topic of bicycling advocacy, for special bicycle facilities as if they were some kind of panacea. It is too easy to push for simple solutions to complicated problems.

And also as to bicycling, here’s one specific I noticed in the video: there’s not one single bicyclist in it, from beginning to end. I think that deserves mention. I don’t know whether bicyclists were there but were intentionally not shown, or whether there just weren’t any. In either case, I regard that as unfortunate and I’d like to know why!

Posted in Bicycle facilities, Bicycling, Crashes, Traffic Signals | Tagged , , , , , , , , , , , , | Leave a comment

Safety in numbers: if and when so, why?

Posted on October 15, 2010 by jsallen

I write here in response to an online article in the Grist blog, which addresses the concept of “safety in numbers” among cyclists and pedestrians. As is all too common, the article takes this phenomenon for granted, and ascribes it entirely to changes in behavior of motorists. There is no mention of changes in behavior of cyclists and pedestrians themselves.

The concept of “safety in numbers” is often applied to animal behavior, and a couple of examples might be useful. Here’s one from the University of Rhode Island Sea Grant program:

A potential predator hunting for a meal might become confused by the closely spaced school, which can give the impression of one vast and frightening fish. Additionally, there is the concept of “safety in numbers”—a predator cannot consume an unlimited quantity of prey. The sheer number of fish in a school allows species to hide behind each other, thus confusing a predator by the alteration of shapes and colors presented as the school swims along. Of course, those on the outside edges of the school are more likely to be eaten than those in the center.

Here’s a video of such behavior.

A herd of animals may actively defend its members, as shown in this astonishing video.

In warfare also, there are issues of safety in numbers, discussed in terms of “swarm warfare“. In some cases, the opposite tactic is applied, for example, in dispersing troops to avoid their all being taken out in a concentrated attack.

Bicyclists and other road users, on the other hand, don’t generally interact like prey and predators, or like armies in battle. I mean, motorists may sometimes be careless. A few may intentionally take risks with the safety of bicyclists and pedestrians, or be in denial about the hazards they pose. Motorists, however, generally aren’t intentionally out to kill and aren’t contemplating having us for dinner. What, then, is the mechanism of so-called “safety in numbers”? When might it exist, and when not?

First, there are different kinds of numbers.

  • The general level of bicycling or walking in a population.
  • Different locations in the same area that have different numbers of bicyclists/pedestrians/motorists, but all from the same general population.
  • Different areas, with different populations and different rates of use.
  • Numbers which increase on particular days, for example in nice weather.
  • A population in the same area but changing over a span of years.

In an earlier post, I examined an Oakland, California study of pedestrian crashes at different intersections in the same community. The researchers’ text claims safety in numbers but the graphs show otherwise: the crash rate was moderately higher at intersections with more pedestrians. It was also higher at intersections with more motorists. It would take further analysis to determine how these two factors correlate with each other.

The well-known Jacobsen study of safety in numbers of bicyclists (also here) compared different communities at the same time. It also has been criticized (including in the Oakland study) for faulty math that shows a hyperbolic descending curve even if the input data are completely random.

The Jacobsen study also says:

Whose behavior changes, the motorist’s or that of the people walking and bicycling? It seems unlikely that people walking or bicycling obey traffic laws more or defer to motorists more in societies or time periods with greater walking and bicycling. Indeed it seems less likely, and hence unable to explain the observed results. Adaptation in motorist behavior seems more plausible and other discussions support that view. Todd reported three studies showing “motorists in the United States and abroad drive more slowly when they see many pedestrians in the street and faster when they see few”.27 In addition, motorists in communities or time periods with greater walking and bicycling are themselves more likely to occasionally walk or bicycle and hence may give greater consideration to people walking and bicycling. Accordingly, the most plausible explanation for the improving safety of people walking and bicycling as their numbers increase is behavior modification by motorists when they expect or experience people walking and bicycling.

This dismisses the learning experience: that the more people walk or ride bicycles, the better they get at recognizing and avoiding hazards. Other studies have demonstrated that the length of bicycling experience has a dramatic effect on crash rates. This occurs whether or not people are obeying traffic laws or deferring to motorists. Jacobsen identifies bicyclists as being able to take no active measures to improve their safety.

In order to maximize safety, we need to know not only what happens, but also why. My own opinion is that there is generally an increase in safety over time as the number bicyclists and pedestrians increases. This occurs due to a number of different factors but also is impeded by others.

Some factors increasing safety:

  • Longer experience, on average, of cyclists
  • Cyclists’ better understanding of how to ride safely in a group
  • Higher average age of cyclists
  • Multiplicative effect of mentoring of cyclists by other cyclists (especially, children by parents)
  • Change in attitude of motorists
  • Presence of one cyclist directly increasing the safety of another by blocking traffic.
  • Better facilities design, resulting from a more refined understanding of how to provide for bicyclists’ safety.

Some factors decreasing safety:

  • Entry of new and inexperienced cyclists into the mix
  • One cyclist’s concealing another from view when there many
  • Sense of entitlement leading to scofflaw behavior
  • False sense of security — “follow-the-leader” behavior when riding in a group
  • Rush to build bicycle facilities, resulting in design compromises and inherent flaws
  • Facilities that favor the least skillful, but are overprotective and frustrating for the more skillful, promoting scofflaw behavior
  • Placing all eggs in the basket of “safety in numbers” and neglecting other approaches to increasing safety

There’s clearly much more research yet to be done in this field.

Posted in Bicycle facilities, Bicycling, Reviews | Tagged , , , , , , , , , , | 14 Comments

Support petition candidates in League of American Bicyclists election.

Posted on October 12, 2010 by jsallen

[This post is about an election in 2010]

Three League of American Bicyclists members are petitioning to run as candidates for the Board of Directors. They have asked me to post their message, and here it is. I have signed their petition and I suggest that if you are a League member, you also do.

Did you know that by next year, nearly half of the LAB Board (7 of 15 members) will be appointed? This means that seven board members will not feel a commitment to be responsive to members. The League board changed the Bylaws this July — without asking members whether they approve of having their influence weakened.

We think this is unacceptable in a membership organization. Please help us protect the rights of all members. Support candidates who will work to make all Board members elected and responsive to members, and who will work to re-direct LAB to better defend cyclists’ rights and represent members’ interests.

In addition to appointing the unelected directors, the Board controls who can get on the ballot. They accepted only one reform candidate, Bill Hoffman, who is currently on the Board. This means John Brooking, Eli Damon and Khal Spencer must collect over 1000 petition signatures to get on the ballot.

We hope you will sign our ballot petition. You can sign online at http://www.PetitionOnline.com/0league0/petition.html [no longer available]
If you want more information and especially if you would like to help us collect signatures, please see http://www.labreform.org/campaign/ [no longer available].

We apologize if you get more than one request to sign our ballot petition. Time is critical — we must receive all petitions by October 20 and we need many signatures. We are contacting affiliated clubs, cycling lists, cycling instructors and anyone we can. You can help by forwarding this message and the petition link to any LAB members you know.

After you have signed and returned the petition, please let us know so can verify that all petitions are counted.

And please remember to vote for us and for Bill Hoffman when balloting opens on Dec. 1.

Thank you very much for your support and vote.

John Brooking

Eli Damon

Khal Spencer

Posted in Bicycling | Tagged , , , , | 1 Comment