John S. Allen's Bicycle Blog

Bicycle touring is a great way to break out of daily routine, and beyond that, into the unexpected.  That’s one reason I like it.

My son Jacob, age 19, and took on a little 2-day bicycle tour Thursday and Friday. It was his first bicycle tour ever.

Last Thursday morning, we drove to Falmouth on Cape Cod, parked at a friend’s house and rode the Shining Sea path to the Steamship Authority ferry terminal in Woods Hole — took the ferry to Martha’s Vineyard and stayed overnight at the HI-AYH hostel –  which is really nice these days. They even make pancakes for breakfast, included in the modest price (but do bring earplugs in case someone snores — dorm accommodations).

At the hostel, we encountered Francine, who had been a participant in a bicycle tour to the Cape that I led 25 years ago, and which had stayed at the same hostel. Jacob got to hear Francine’s angle on funny stories from that tour which I had just told him the same day. I spoke with a couple of German university students who confirmed that he German spelling reform has led more to confusion than to anything else, just as my Bicycling Street Smarts translator says.

Friday morning, after leaving the hostel, while riding on the path in the state park, we got stopped for two security checks, including baggage inspection. About a mile after the second security check, a group of about 30 cyclists approached. One face was instantly recognizable.

I raised my little digital camera and pressed the button, then lowered it.

“Good morning, Mr. President” I said.

“Good morning, he replied.

After the group had passed, I checked my camera. It had been in “review” mode. No picture.

Given the security issues, I decided it would be very much the best just to keep on riding rather than to turn around and try to get one.

Not bad though for Jacob’s first bicycle tour. Jacob wants to go touring again. We were well-matched for speed on this one, but if he rides enough, we’ll have to go over to the tandem because I won’t be able to keep up with him otherwise!

Bicycling

A showcase example for  Federal promotion of special bicycle facilities in the USA has been laid down on Pennsylvania Avenue in Washington, DC, with bike lanes extending between the Capitol and the White House.  It’s quite a show, but it didn’t turn out exactly as planned.

Well, on with the show. On June 7, 2010 — as described in a press release and videos — League of American Bicyclists President Andy Clarke, Representative James Oberstar (D-MN), NBA basketball star Caron Butler  and the Crown Prince of Denmark were out on Pennsylvania Avenue expressing their enthusiasm for the bike lanes, riding bicycles supplied by Specialized, a major American bicycle supplier. Why the Crown Prince? American bicycle facilities advocates hold Denmark up as an example. Why industry involvement? Because the industry sees special facilities for urban cycling as the key element in propelling the next wave of bicycle sales. Why politicians? Because public funding would have to pay for the facilities. Why Caron Butler? I don’t know!

Pennsylvania Avenue bike lanes, May 11, 2010

But, in its press release, the League of American Bicyclists borrowed a basketball expression, describing the Pennsylvania Avenue project as a “slam dunk.”

This wasn’t the first praise for the project. A month earlier, on May 12, the photo at the right appeared in a message sent to an e-mail list of the Alliance for Bicycling and Walking (a consortium of state and local advocacy groups) among other lists. The iconic bicyclist is riding off into the sunrise, toward the Capitol. In the background, tourist buses queue for their first run of the day. Accompanying text, by League of American Bicyclists board member Tim Young, reads:

I was just in Washington and rode the new Pennsylvania Ave Bike Lanes, so fun the paint was still drying. Awesome to ride from the White House on one end to Congress on the other, and have such huge dedicated space for bikes. You have to ride it!

Center lane was an unexpected design for me, but it works if you follow the signals and signs. Its casual riding, so much room and buffer, and the road is not that busy for its size, I understand about 30,000 ADT. You can see from this photo the massive bus use, so the curb lane is full of conflicts. The center rides fine. The only unhappy campers were taxi drivers wanting to make U turns mid block.

Photo: Mike Tongour, Bikes Belong lobbyist, rides towards Capital Hill.

(Bikes Belong is a bicycle industry lobbying organization which, among other efforts, lends substantial financial support to the League.)

Young may, however,  have spoken too soon about the ample width of the bike lanes. They had been installed over the weekend of May 1 and 2; promptly on Monday, May 3, the Mid-Atlantic division of the American Automobile Association issued a press release  suggesting that they would worsen traffic congestion. That press release is no longer available on the AAA Web site, but you may read it here. It has in turn been widely criticized by bicycling advocates, for example here. and the criticism has been echoed in some media outlets, for example, here. The Washington Area Bicyclist Association, the local bicyclists’ advocacy group, asked its members to support the lanes, here.

Bicycling advocates pointed out that Pennsylvania Avenue was already relatively lightly traveled, as the blocks nearest the White House had been permanently closed to motor traffic following the 1995 bombing of the Federal Building in Oklahoma City. An AAA member poll, cited in the press release, indicated that only 20% would feel compelled to become bicycle commuters if traffic congestion worsened. The bicycling advocates turned this finding on its head: 20% is a higher bicycling mode share than in any US city. Copenhagen’s bicycle mode share is hardly any larger, though its bicycle-to-work/school mode share is around 37%.

On May 20, the Washington Post reported that changes in the lanes were in the works. A quote:

Gabe Klein, director of the Department of Transportation, called to clarify that the delay in the opening of the bike lanes on Pennsylvania Avenue might not result in the lanes growing tighter.

Klein disclaimed bowing to any pressure and said the lanes needed to be “redesigned” to enhance the safety of bicyclists.

The article also described a Bike to Work Day rally to be held the next morning in support of the lanes and to be addressed by Rep. Earl Blumenauer (D-Portland, Oregon).

Two weeks later,  on June 7, Clarke, Oberstar, the Crown Prince and NBA basketball star Caron Butler were out in the bike lanes for their media event. Clarke returned to his office to describe the project as a “slam dunk.” In the light of the proposed changes, this event can be construed as support of the project in the face of a threat.

Slam dunk indeed. It turned out that bicyclists were slammed, and dunked.

On the next day, June 8, the Post published an article describing the planned modifications. Travel lanes that had been converted to bike lanes were to be restored, and the bike lanes moved to the median (growing tighter, in spite of what Mr. Klein had said). The article reports that the AAA applauded this change, while the Washington Area Bicyclist Association, the local bicyclists’ advocacy group, expressed concerns about conflicts between bicyclists and pedestrians.

The changes were made. On June 22, the lanes officially opened. On July 3,  independent journalist Matt Johnson rode the lanes and took photos. He wrote an article and posted his photos on Flickr. He gave anyone permission to use them, with attribution. I thank him.

The title of the article, “Pennsylvania Avenue Bike Lanes Still have a Few Flaws“, suggests that the lanes had been improved. The contents of the article and the photos show quite the opposite.  The space for bicyclists had been significantly reduced, and bicyclists were thrown into conflict with pedestrians at intersections.

Here’s a photo of the bike lanes, looking west across 9th Street NW, taken in mid-May. The layout is already rather strange, with turning bicyclists — including right-turning bicyclists — directed to the merge left. The right-turning bicyclists have to  recross the stream of through-traveling bicyclists to get to the crosswalk which they are supposed to use.

Bike lanes at 9th St. NW, mid-May, 2010

Below is another photo which Johnson took at the same location on July 3. (You may click on either photo for a larger view.)

Bike lanes at 9th St. NW, July 3, 2010

The space between the two lanes of opposite-direction bicycle traffic is gone — the available width is indeed tight if the lanes are to carry any substantial volume of bicycle traffic. But the intersections are weirdest of all. Through-traveling bicyclists now ride up and over the median refuge where pedestrians wait. The bike lanes are now immediately adjacent to the black, handlebar-snagging bollards that protect the traffic-signal poles. Turning bicyclists have it stranger yet: they are aimed straight for the traffic signal at the center of the median.

The one change that anyone could contend is a safety feature is the row of flex posts between each bike lane and the adjacent travel lane, intended to keep motorists from encroaching into the bike lane. Safety feature? Well, maybe. A flex post is harmless to a car, but it can easily take down a bicyclist.

A search of the League’s e-mail blasts and blog turned up blog posts responding to the AAA press release and reporting on the opening celebration for the reconfigured bike lanes on June 22, as well as the “slam dunk” post and a couple of others featuring the Crown Prince, but no mention of the redesign. Comments on the redesign turn up several times in a record of a live online chat with Washington Area bicyclist Association Executive director Shane Farthing.. (Search on “Pennsylvania” inside the post to find them.)

Enough for now. This article is intended as a brief history. I’ve only addressed technical issues to the extent necessary to move the history along. I’ll be addressing them in detail in another post.

Bicycling

Though they are not first to do this, Dutch researchers have calculated the effects of different travel mode choices on life expectancy. The study is called Do the Health Benefits of Cycling Outweigh the Risks? The researchers based their calculations on an examination of traffic accidents, exercise and air pollution.

Good enough, but  excuse me if I’m about to restate the obvious. There are also a quality-of-life issues, and they aren’t the same for everyone — far from it.

Time spent traveling and earning income to pay for the travel can add up to many years of a person’s life.  This time could be enjoyable, or  a dull chore, or a drudge. The cost may be trivial to one person, but a major burden to another.

The ability to work, read or converse is a time saver with public transportation or carpooling; less so for walking, even less for bicycling; not for driving alone unless perhaps listening to an audiobook or talking on a cell phone — well, let’s not go there. Aerobic exercise when bicycling or walking is a time saver for people who value the exercise, and it also increases life expectancy. Need I say, physical fitness also increases quality of life.

Time may be spent waiting for the bus or train to arrive, waiting in a traffic jam, waiting for traffic signals, hunting for a parking space, walking from and to that parking space.

Owning and operating a private car is expensive to the individual; public transportation, generally less so; bicycling, even less and walking only wears out shoes occasionally. However, the infrastructure costs of all of these modes of travel are largely subsidized from public funds.

At this point, we get into issues of the individual vs. society.  Examples: a private motor vehicle is a major time saver unless there are too many of them, causing traffic congestion, air pollution, global warning. Then the interests of society at large suggest investment in other modes, while the interest of individuals still favors the private car — for other reasons as well, particularly weather protection,  convenience in transporting passengers and cargo, and the low marginal cost of each mile of travel relative to the fixed cost of car ownership.

Which leaves us more or less the situation we are in now. Investment in public transportation as well as innovative solutions such as convenient car and bicycle rental can help shift the balance, but worldwide, the private car continues its upsurge,.

Bicycling

Double Crossover Diamond Interchange

A document from the Turner-Fairbank Highway Research Center of the US Federal Highway Administration describes a new concept in freeway interchanges, the Double Crossover Diamond Interchange.

The novelty here is that the overpass operates with traffic on the left, in the USA, reducing the number of conflicts and signal phases.

Figure 1  (a photo) in the PDF document and Figure 3 (a diagram) show how pedestrian traffic might be accommodated, except that Figure 3 does not show the pedway in the median that is shown in Figure 1. Apparently, in Figure 3, there would be sidewalks along the outside instead.

Figure 2 shows no pedestrian accommodation, and there is an unsignalized two-lane on-ramp at the lower right.

The high barriers adjacent to the median in Figure 1 screen glare from the wrong side of headlamp beams.

The word “bicyclists” appears in the introduction, but the document does not address accommodation of bicyclists.

Figure 1 does not show shoulder/bike lane width to facilitate on-road bicycle movements. Bicyclists might merge left of the off ramp and enter a bikeway/pedway in the median immediately after the crossover, reducing width requirements for the overpass. But then they still must pass the traffic island and cross the on ramp after the freeway, or else enter the traffic island and use the set-back crosswalk on its far side — a circuitous route. Using the pedestrian route for the whole way is even more so.

As the crossovers have to be signalized anyway, signalization of the on ramps would also improve flow on the overpass. Alternatively, the on ramps might be placed at a sharp angle with a small-radius turn, to slow entering traffic. If the on ramps are treated in one of these ways, if there is sufficient width before and after the bridge, and if there is a central bikeway/pedway, bicycle travel could be quite convenient — though snow clearance issues in winter could require bicyclists to ride across the overpass in the roadway, and also make travel difficult for pedestrians.

Another possibility would be a bicycle/pedestrian underpass at each of the four ramp locations, with sidewalks along the outside of the overpass. As the ramps already must be elevated, adding these underpasses would not substantially increase the cost of the project.

An “upside-down” version of this intersection is also conceivable, with the freeway above the road that crosses it. Sight lines would not be as long; the crossing in an underpass would be noisy and relatively dark; bicycle/pedestrian grade separations, if used, would be overpasses instead, and more expensive.

Bicycling

A correspondent on the Charles River Wheelmen bicycle club e-mail list reports that a company called Liberty Tire has started a program to recycle bicycle inner tubes. This is reported in the Journal Waste and Recycling News, but “[i]t doesn’t look like they have anything in Massachusetts.”

Bicycle shops must replace inner tubes, rather than patch them, in order to avoid potential liability risks. Recycling inner tubes will probably provide a net environmental benefit as it concerns repairs at shops.

The proposal could, however, encourage individual cyclists to replace their punctured inner tubes, rather than to patch them. The manufacture and transport of more inner tubes would probably increase the environmental impact vis a vis cyclists’ patching and re-using their tubes. Increased manufacture, transport and sale of inner tubes work to the benefit of Performance Bicycle and other suppliers, but are an environmental detriment.

It is often faster to replace a tube while out on a ride than to patch it (exception: on a wheel that is difficult to remove, such as one with a coaster brake), but a cyclist should always carry a patch kit anyway, in case of more than one flat. A punctured tube may be patched at leisure later, avoiding the need to buy a new one. A properly-patched tube is reliable.

Bicycle inner tubes in any case pose a much smaller recycling issue than motor vehicle tires.

The article from Waste and Recycling News follows. I find one statement in it really odd. The $5 offered per used inner tube is about twice the cost of most new bicycle inner tubes. Can this be right? I’ll leave it to you to figure out the consequences if it is!

Liberty Tire, company to recycle used bike inner tubes

June 17 — Liberty Tire Recycling of Pittsburgh has partnered with Performance Bicycle to increase recycling of old bike inner tubes across the U.S.

“By collecting and recycling used inner tubes, Liberty Tire Recycling and Performance Bicycle are providing cyclists with an opportunity to prevent the tubes from ending up in a landfill,” said Jeff Kendall, CEO of Liberty Tire. “The tubes we collect and recycle will be transformed into innovative, eco-friendly products that make people’s lives better and safer — everything from rubberized asphalt for highways to rubber mulch for playgrounds and parks.”

Through the partnership, people who bring their old inner tubes to participating locations will receive a $5 for each tube returned.

For information about dates and locations, visit the Performance Bicycle Web site.

Contact Waste & Recycling News reporter Amanda Smith-Teutsch at 330-865-6166 or asmith-teutsch *at* crain.com.

Bicycling

A procedure exists through the Federal Highway Administration to encourage experimentation in transportation projects. This procedure defines new, nonstandard treatments as experimental, and requires that research data be collected, so that non-standard designs may serve to direct the standards-setting process, a very desirable outcome. In compensation for the burden of conducting research, this procedure exempts projects from liability risks.

But there may be a hitch at the Massachusetts level. Massachusetts General Statutes, Chapter 85, Section 2, does not appear to offer any exemption from the Massachusetts Department of Transportation’s Project Development and Design Guide or the Department’s standard municipal traffic code and amendments to the Manual on Uniform Traffic Control Devices.

Is there a procedure for experimentation? If so, how it is handled and by whom at MassDOT — and if not, how a procedure be established? I have not found a description of such a procedure anywhere.

The relevant wording in the statute is as follows. I have given some organization to the impenetrable block of text on the Commonwealth’s Web page. I have also added a few descriptive notes, which I have boldfaced.

Approval by DOT is not required if installation conforms to its manual.

…Except as hereinafter provided, any rule, regulation, order, ordinance or by-law of a city or town hereafter made or promulgated relative to or in connection with the erection or maintenance of signs, traffic control signals, traffic devices, school zones, parking meters or markings on any way within its control shall take effect without department approval provided such signs, traffic control signals, traffic devices, parking meters, school zones or markings are in conformance with the department’s current manual on uniform traffic control devices and the department’s sample regulation for a standard municipal traffic code; provided, however, that such rule, regulation, order, ordinance or by-law shall not take effect until approved in writing by the department, or be effective after such approval is revoked, if made or promulgated relative to or in connection with the following:

Exceptions, when approval by DOT is required

any way at its intersection or junction with a state highway;

any project which is or was federally aided, in whole or in part;

any traffic control signal or flasher in any city or town which does not employ a registered professional engineer in the commonwealth to design, redesign or change the timing and sequence of signal or flasher;

any sign excluding heavy commercial vehicles;

any school zone establishment or signing in relation to which the city or town intends to seek reimbursement from the commonwealth;

any one-way street sign not placed at an intersection of public ways;

any rule, regulation, order, ordinance or by-law of a city or town which when made or promulgated would exclude motor vehicle travel on any existing way which connects one city or town with another, unless such rule, regulation, order, ordinance or by-law was promulgated in compliance with the following:

1. the rule-making body of the city or town initiating such rule, regulation, order, ordinance or by-law gives written notice of such action to the chief executive officer of the abutting city, town or county into which the said way extends, and
2. a public hearing is held by the city, town or county initiating such alteration, relocation or discontinuance, public notice of which must be published for each of the two weeks preceding such hearing in a newspaper of general circulation in the abutting city, town or county into which the said way extends, and
3. after concurrence in writing by the chief executive officer of the abutting city or town into which the said way extends or his designee. Notwithstanding the foregoing, speed control signs may be established only in accordance with the provisions of section eighteen of chapter ninety.

Penalties

If any city or town installs and maintains any of the aforesaid traffic control devices without either requesting or obtaining the required approval or after being notified of such disapproval, or in noncompliance with said manual, the department shall withhold or withdraw the unexpended balance of any funds assigned to the said city or town under the provisions of section thirty-four of chapter ninety or sections twenty-five and twenty-six of chapter eighty-one.

Any traffic control device which has not been erected or maintained in accordance with the foregoing provisions may be removed by or under the direction of the department and be stored by the department until claimed by the owner or, if not claimed within sixty days after written notice to said owner, may be disposed of at the discretion of the department. Color and arrow indications of traffic control signals shall have the commands ascribed to them in said manual.

Flashing white walk signal is prohibited.

The use of the flashing white walk pedestrian signal indication, as defined in the official standards of the department, is prohibited. The superior court shall have jurisdiction in equity to enforce the provisions of this section and section one, and also sections one and four of chapter eighty-nine and any rule or regulation made thereunder or to enjoin the violation thereof.

Signs warning of children with disabilities are exempted.

The provisions of this section shall not apply to the installation by any city or town, on any way within its boundary, of signs warning motorists of the presence of blind, deaf or otherwise handicapped children in the vicinity.

Since 2002, I have been a member of the National Committee on Uniform Traffic Control Devices Bicycle Technical Committee, which reviews projects that relate to bicycling. No requests to experiment have come to the Bicycle Technical Committee from Massachusetts, though there has been a fair number of projects which do not conform to standards.

The present situation on the one hand discourages experimentation, and on the other hand encourages installation of nonstandard treatments without the benefits of experimentation. Compounding this problem, the Commonwealth is not policing the work of cities and towns. It is not necessary to look far to find installations which fail to comply with statute. It causes real problems when, for example, signs are difficult to interpret, or unreadable at the distance from which drivers view them. Consider, for example, these examples of pedestrian signs.

Lax enforcement by the Commonwealth of design standards in local projects has allowed this situation to continue. Sovereign immunity laws in Massachusetts allowing limited recovery have prevented pressure to enforce the standards by way of civil actions.

Nonstandardization is an acute issue with all types of facilities, but it is particularly acute as it applies to bicycle and pedestrian facilities, where new treatments are frequently being suggested and implemented. We suffer at the same time from a lack of standardization, and from a lack of guidance in experimentation.

Bicycling

“Your 25-pound bicycle is no match for a 10,000 pound truck.” You’ve probably heard that before.

So, if you collide with a 10,000 pound truck, the impact will be much, much worse than if you collide with a passenger car, or another bicyclist, or a pedestrian, because the truck weighs so many times more than your bicycle.

By the same reasoning, you should be much worse off yet if you simply fall and collide with the planet Earth. It is so much heavier than that truck…

Hmm, but we’ve all fallen off our bicycles a few times, mostly without serious injury.

I don’t want to collide with a truck — or a car, or another bicyclist, or the planet Earth. But let’s look at some basic physics.

First of all, the mass of the bicycle isn’t the issue. The rider accounts for most of the mass of the bicycle/rider system.

But also, the severity of a collision doesn’t increase directly with mass. It depends on the severity of the impact.

Consider two bicyclists, a perfect match for each other, riding toward each other at the same speed and colliding exacttly head-on. They will both come to a complete stop. This impact would be the same if you put a brick wall, or a sheet of paper, between the two bicyclists.

Now, suppose that the truck is headed toward the bicyclist at the same speed as the other bicyclist. How much more severe is the impact?

Not hundreds of times, but four times. The energy dissipated in a head-on crash is as the square of the speed. The square of 2 is 4. The truck is so much more massive that the bicyclist is pushed back at almost the truck’s speed. It’s almost the same as riding into a brick wall at twice the bicyclist’s speed.

Severity of impact is much more about speed than about mass. The severity of a bicyclist’s collision with a motor vehicle is almost entirely in proportion to closing speed, all other things being equal. The only exception is if you go underneath and get run over. Then, the vehicle’s mass does matter. Getting run over either by a car or a or by a truck is most likely deadly.

Bicycling

P. M. Summer is the former bicycle coordinator of Dallas, Texas, who was removed from his job because of his conservative approach to bicycle facilities. I post the following with his permission:

There is a whole new breed of bicycle professional out there. They aren’t what we usually think of as cyclists, much less traffic engineers or transportation planners. They are most often urban planners and landscape architects, who have become virtual social engineers. They see their job as changing the way dumb old Americans live in favor of the ways enlightened Low-Country Europeans live.

The bicycle is a means to that end. In their eyes, the bicycle isn’t a vehicle (as code defines it), and never has been. It’s a shoe with wheels. Cynically, they usually add “pedestrian” to their title, while short-shifting pedestrians in favor of “pedalcyclists”.

Most of these new bicycle professionals have never used a bicycle as a regular transportation device (including the gentleman hired to replace me), believe the road (any road) is inherently unsafe for cyclists, and believe that a segregated network is the enlightened (and sole) way to dramatically change mode share.

It’s almost impossible to argue with folks like this, because the only common point of reference is the word “bicycle”, and by “bicycle”, they mean something very different than what I, or others who think like me, do.

The problems we point out about how traffic operates don’t register, because bicycles can never be “traffic” in their eyes. Traffic is always the bicycle’s enemy, and never the bicycle’s environment. People who operate bicycles are like swimmers in shark-infested waters to them. The brave and fool-hardy only need apply. “Normal” people know better, and stay on the side-path/walk/track/gutter.

Fifteen years ago I had the Texas DOT Bicycle Coordinator plead with me to quit defending placing bicycle facilities (signed bike routes) on streets with lanes less than 14 ft. wide. When I explained to him that I preferred 10 ft. lanes, I thought he was going to have a heart attack. “You can’t put cyclists in the way of cars!” he said.

There is a growing “bikes belong off the road” sentiment. Cycling Advocates are slow to support cyclists like Eli [Damon], or Reed Bates, or Fred U., [who have been harassed by police for exercising their legal right to use the road] because to defend them would be to say that it’s not unsafe to ride on the roads… and LAB, ABW, and APBP [the League of American Bicyclists, Alliance for Bicycling and Walking and the Association of Bicycle and Pedestrian Professionals] can’t afford to admit that.

Why can’t these new bicycle advocates admit that bicycles can easily operate as part of the transportation mix, instead of having to be segregated from it? To admit that makes the extravagant demands for special facilities clearly just that: extravagant demands. Andy Clarke, then of BikeFed [the Bicycle Federation of America, now the National Center for Bicycling and Walking; now Clarke is President of the League of American Bicyclists] once described the cost for a segregated bicycle facility as being “mere decimal dust” compared to the cost of automobile projects. That ‘decimal dust’ has turned into hundreds of millions of dollars in consultant and lobbyist fees, as well as “bicycle planner” salaries. Admitting that most of these facilities aren’t necessary for safe and easy bicycle transportation endangers too much money currently being poured into the new cottage industry of “Amsterdamning America”, and threatens too much personal power. Politicians, eager for popular (if unproven) quick fixes, are far more likely to endorse feel-good projects using other people’s money than they are to call for better educated and trained cyclists.

You may find more from P.M. Summer on his own blog.

Bicycling

Dr. Anne Lusk made an interesting comment on red lights: (quote is here):

Female bicyclists in England are being killed at a higher rate than
males because females wait for the green light to proceed and then are
hit by turning trucks,” said Anne Lusk, a Research Fellow at the
Harvard School of Public Health and active supporter of the BCU. She
suggests that the majority of car drivers and bicyclists are
conscientious and that warnings, instead of tickets, would improve
safety, increase bicycling, and foster good will.

Lusk is neglecting issues with bicyclist behavior that lead to such a result. Consider the probable mechanism:

Scofflaw male cyclist runs red light, and usually gets ahead of first-in-line turning motor vehicle before it turns.

Law-abiding female cyclist waits to the left (in England) of that vehicle and gets left-hooked when the light changes.

So, Lusk is making an argument for — what? Running red lights? — based on different kinds of poor behavior by males and females, exacerbated by traffic lights that cause delay when there is no cross traffic.

Those of us who understand the risks neither run red lights nor position ourselves where we are endangered by turning traffic. My advice is to merge far enough from the edge of the road to forestall a hook turn, and if filtering forward, to wait behind the first vehicle, where the driver of the second one can see me and yield to me.

And that in spite of a healthy a level of testosterone!

Bicycling

The University of California has published a study of pedestrian crashes in Oakland, California,

The Continuing Debate about Safety in Numbers—Data from Oakland, CA
Judy Geyer, Noah Raford and David Ragland, Traffic Safety Center;
Trinh Pham, Department of Statistics, UC Berkeley
UCB-ITS-TSC-2006-3

The full report is available online:

http://www.escholarship.org/uc/item/5498×882

John Forester, founder of the Effective Cycling program of cyclist education, and statistician, has demonstrated that the Safety in Numbers claim of Jacobsen (also cited in the Oakland paper) is faulty. Due to faulty math, a random set of numbers will generate the curve that apparently shows a decreasing crash rate with increasing numbers of users. This is not to say that the safety-in-numbers claim is false, but rather that Jacobsen has provided no evidence to support it. (Forester also questions Jacobsen’s explanation for safety in numbers as applied to bicyclists, but that’s a different issue.)

The Oakland report expresses the same complaint about Jacobsen’s math, and goes on to use better math to look for answers. Here’s a quote from page 5 (PDF numbering) of the Oakland report:

However, others are concerned that correlating collision rate (C/P) with pedestrian volume (P), (where C equals collisions and P equals pedestrian volume) will almost always yield a decreasing relationship due to the intrinsic relationship of the variable P and the fraction 1/P.

Tom Revay has generated a Microsoft Excel Workbook demonstrating how Jacobsen’s curve may be generated with  random data. Press the F9 key on a PC to refresh the random data. (Press Command [Apple] and = at the same time on a Mac. I thank Dan Carrigan for this information)

The Oakland study came up with some interesting and intriguing results. Here are a few; please correct me if I am wrong:

Figure 4, p. 17, Pedestrians vs. Collisions/Pedestrian

• The graph on p. 17, PDF numbering (click to see a larger version) shows the characteristic downward curve due to faulty math. However, the curve slopes back upwards for the intersections with the very highest numbers of pedestrians.
  

  Figure 3, p. 16, Pedestrians vs. Collisions

  A better graph (graph on p. 16, PDF numbering, click to see a larger version) shows crashes increasing with a steeper slope for the higher-volume intersections, worst at the intersections with the highest volume. Crash numbers are low enough, though, that the results for individual intersections are not statistically significant.

• The Oakland study examines different intersections in the same community over the same time period rather than the same intersections at different times, or different communities with different volumes of pedestrian and vehicular traffic. The study can establish whether the safety in numbers effect applies only under the conditions it examined. Data from different times of day might possibly be checked against traffic volumes, though the results would be less robust and effects of lighting, alcohol use etc. would make them harder to interpret.
• It is clear that a few intersections are outliers, with many more crashes than others. These intersections would be high on a priority list for improvements — though the actual numbers for individual intersections, again, are too low to be statistically significant.  The problem with lack of statistical significance highlights the importance of applying research data and operational analysis in determining where to make infrastructure improvements — crash data for an individual intersection are not statistically robust unless the intersection has an extremely bad problem. You apply research results and operational analysis so you can avoid collecting data on each intersection by killing and injuring people.
• (See Results, p. 9, PDF numbering) Number of lanes on the primary and secondary streets, and number of marked and unmarked crosswalks, did not correlate with crash rates! (But note that this result is consistent with data on bicycling showing that riding on arterials is safer than on residential streets).
• Despite the safety-in-numbers finding, the intersections with the largest numbers of crashes are still those with high pedestrian volumes. Increasing numbers decrease the rate of crashes, but not the number of crashes.
• 

  Figure 5, p. 18, Vehicles vs.Collisions/Pedestrian

  The crash rate increases for pedestrians as the number of vehicles increases (page 18, PDF numbering), though less rapidly than the number of vehicles. Is there a safety in numbers effect for vehicle operators as the number of vehicles increases? Yes, the likelihood that any particular driver will collide with a pedestrian decreases with the amount of vehicular traffic passing through an intersection — though the study doesn’t report this. The study doesn’t answer whether the result is achieved by improved signalization at high-volume intersections, or by depressing pedestrian volume (risk homeostasis), or by what other effect. The study also doesn’t say anything about crashes overall, as it doesn’t report on crashes not involving pedestrians.

All in all — interesting, intriguing, and careful research — but more research is needed!

Bicycling