Tag Archives: Portland

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

Truck side skirts: reliable way to prevent cyclist fatalities?

No, not reliable. And they are also supposed to confer an aerodynamic advantage. Some do, some don’t.

Some have a smooth surface which can deflect a cyclist. That is still no guarantee that the cyclist will escape serious injury or death. Other side guards are only open frameworks which can catch and drag a bicycle. A lot of what I have seen is little more than window dressing.

The side guard in the image below from a post on the Treehugger blog has no aerodynamic advantage and could easily guide a cyclist into the rear wheel of the truck.

Photo of truck side with guard from Treehugger blog.

Photo of truck side with guard from Treehugger blog.

A cyclist can easily go under the side guard shown in the image below, from a Portland, Oregon blog post. A cyclist who is leaning against the side guard is guided into the sharp edge of the fender bracket and fender, and the front of the turning wheel, which can pull the cyclist down. There is another wheel behind the one in the photo.

Side guard on City of Portland, Oregon water transport truck

Side guard on City of Portland, Oregon water transport truck

The side guard on a Boston garbage truck in the photo below — my own screen shot from the 2013 Boston Bikes annual update presentation — is only an open framework which could easily catch and drag a bicycle.

Side skirt on City of Boston garbage truck

Side skirt on City of Boston garbage truck

A truck which is turning right off-tracks to the right. A cyclist can be pushed onto his/her right side, and goes under, feet to the left, head to the right. On the other hand, if an overtaking truck contacts the left handlebar end, or if the right handlebar end contacts a slower or stopped vehicle or other obstruction, the handlebar turns to the right and the cyclist slumps to the left, headfirst.

To be as effective as possible for either aerodynamics or injury prevention, side guards must cover the wheels. Though that is practical, none of the ones shown do.

But no practical side guard can go low enough to prevent a cyclist from going underneath. The side guard would drag  at raised railroad crossings, driveway aprons, speed tables etc. Even if the side guard did go low enough, it would sweep the fallen cyclist across the road surface, possibly to be crushed against a parked car or a curb.

Fatalities have occurred when cyclists went under buses, which have low side panels — but the wheels are uncovered. The Dana Laird fatality in Cambridge, Massachusetts is one example. Ms. Laird’s right handlebar end is reported to have struck the opening door of a parked vehicle, steering her front wheel to the right and toppling her to the left.

Dana Laird fatality, Cambridge, Massacchusetts, 2002

Dana Laird fatality, Cambridge, Massachusetts, 2002

The bicycling advocacy community, as shown in the blog posts I’ve cited, mostly offers praise and promotion of sub-optimal versions of side guards, a measure which, even if executed as well as possible, offers only a weak, last-resort solution to the problem of bus and truck underruns.

Most of the comments I see on the blogs I linked to consider it perfectly normal for motor traffic to turn right from the left side of cyclists, and to design infrastructure — bike lanes in particular — to formalize this conflict. The commenters also would like to give cyclists carte blanche to overtake close to the right side of large trucks, and place all the responsibility on truck drivers to avoid off-tracking over the cyclists.

Cyclists are vulnerable road users, but vulnerability is not the same as defenselessness. It is rarely heard from today’s crop of bicycling advocates, but a cyclist can prevent collisions with trucks and buses by not riding close to the side of them. There’s a wild contradiction in playing on the vulnerability, naiveté and defenselessness of novice cyclists to promote bicycle use with measures — particularly, bike lanes striped up to intersections — which lure cyclists into a deathtrap. Regardless of whoever may be held legally at fault in underrun collisions, cyclists have the ability to prevent them, and preventing them is the first order of business.

Want to learn how to defend yourself against going under a truck? Detailed advice on avoiding bicycle/truck conflicts may be found on the Commute Orlando Web site.

Additional comments about the political situation which promotes underrun collisions may also be found on that site.

Scaling up and scaling down

New York bicycling advocate Steve Faust has stated that some ways of accommodating bicycling do not “scale up” — that is, they work with small numbers of cyclists, but less well with larger numbers.

His central complaint is that use of roadways with no special bicycle facilities, according to the conventional rules of the road, does not scale up well.

I might put that a bit differently. After all, more cyclists need more room. Mass rides such as New York’s own 5-Borough Tour avoid special bicycle facilities and occupy the entire width of Manhattan’s multi-lane avenues. Motor vehicles are excluded while these rides pass through. Interaction within the group of many thousands of cyclists is for the most part according to the conventional rules of the road, and falls short only in that many of the participants are inexperienced.

On roadways carrying both cyclists and motorists, cyclists inconvenience motorists when the motor traffic could go faster — that is, when there are many cyclists and few enough motorists that they could travel unimpeded, if not for the cyclists. Motorists inconvenience cyclists when motor traffic is congested, and stopped or traveling slower than cyclists might want to go. Level of service always declines as a road becomes more congested, and it declines faster when vehicles have differing speed capabilities.

On the other hand, there also are situations in which operation as intended does not scale down to smaller numbers.

Motorists are more likely, for example, to yield to a crowd of pedestrians than to a single pedestrian.

Another example is the leading pedestrian interval: the walk signal goes on a couple of seconds before motorists get the green light. The leading pedestrian interval is intended to get pedestrians moving out into the intersection before motor traffic can begin to turn across a crosswalk, encouraging motorists to yield to the pedestrians. The same approach is used sometimes on bicycle facilities, for example on the Boulevard de Maisonneuve bicycle sidepath in Montréal, Québec, Canada. But a leading interval only works if there is someone waiting to cross when the signal changes. With smaller numbers, so the first pedestrian or bicyclist reaches the crossing after the motorists get their green light, the leading interval’s only achievement is slightly to reduce the capacity of the intersection.

The same issue can occur with any “conflict zone” with poor visibility as users approach, including the “bike box” or bicycle waiting area ahead of the stop line for motorists at an intersection. Once one cyclist is in a “bike box”, a motorist is unlikely to move forward, because that would require running over the cyclist. Therefore, the bike box is then safe for the entry of other cyclists, at least into the same lane in which the first cyclist is waiting.

The”bike box” works as intended when there are large numbers of cyclists so the first one arrives well before the traffic signal turns green.

If there are few cyclists, so the first one is likely to arrive just as the traffic signal turns green, then there is the potential for a right-hook collision, or a motorist’s colliding with a cyclist swerving into the bike box.

Safety requires that there be enough cyclists that early-arriving ones block the way of motorists, or at least alert the motorists that others may arrive. This safety factor does not scale down to small numbers.

Research in Portland, Oregon shows that only 5% of bicyclists swerve into the bike box when they are first to arrive; about 35% if they arrive later. The reluctance of the first-arriving cyclist reflects risk avoidance to some extent, due to not knowing when the traffic signal will change, but also that the swerve lengthens the cyclist’s trip — none of the Portland bike boxes are designated for left turns. The later-arriving cyclists are to some degree protected by the arrival of the first one, but also they either have to wait behind or move over to the left of that cyclist, into the bike box.

“Safety in numbers” claims become rather interesting when such issues are considered.

The design challenge is to achieve efficiency and safety of all travelers, regardless of whether numbers are large or small.

What color is your bike lane?

Should the pavement in a crosswalk, or special on-street bicycle facility, be painted a special color? Under what conditions? What color?

European countries use color. Let’s look at a few examples and see what they might teach us.

First let me say that my showing treatments here does not mean I endorse them. In the first couple of examples below, running a bike lane around the outside of a roundabout defeats the purpose of the roundabout in maintaining smooth traffic flow. Having cyclists and motorists merge into a single, slow flow of traffic has been shown safer for the cyclists too.

That said, this pink bike lane is in Thisted, Denmark — photo taken in 2006.

Roundabout with pink bike lane, Thisted, Denmark. Photo by Dan Carrigan

Roundabout with pink bike lane, Thisted, Denmark. Photo by Gordon Renkes.

This sea-blue bike lane in another roundabout is in Lyngby, Denmark.

Roundabout, Lyngby, Denmark, with blue-painted bike lane. Photo by Ryan Snyder from 2011 Association of Bicycle and Pedestrian Professionals calendar

Roundabout, Lyngby, Denmark, with blue-painted bike lane. Photo by Ryan Snyder from 2011 Association of Bicycle and Pedestrian Professionals calendar.

These bright blue-green lanes are in Copenhagen, Denmark.

Blue-green bike lanes in Copenhagen. Photo by Jon Kaplan

Blue-green bike lanes in Copenhagen. Photo by Jon Kaplan

This red bike lane is in Winterthur, Switzerland.

Bike lane in conflict zone, Winterthur, Switzerland. Photo by James Mackay

Bike lane in conflict zone, Winterthur, Switzerland. Photo by James Mackay

As these photos show, there is no consistent color for carpet painting of bike lanes in Europe. German-speaking countries do appear to have settled on red, but Denmark has used at least three different colors in recent years.

There are issues with the effectiveness of color too.  A couple of years ago, the US Federal Government sponsored a scan tour so traffic engineers and planners from around the country could examine bicycle and pedestrian facilities in Europe. According to one participant in the scan tour, Denmark uses paint only on one or two bicycle routes through an intersection, having found that using it on more routes negates any benefit. Clearly, it is important to address such issues.

What message does the color convey? A common use is to indicate conflict zones — where motorists must expect bicyclists and yield to them. At other times, color is used where no such conflict exists. Here is an example from Bristol, in England where the message is  probably “no cars here”:

Barrier-separated bikeway with colored pavement, Bristol, England. Photo by James Mackay

Barrier-separated bikeway with colored pavement, Bristol, England. Photo by James Mackay

Also according to the scan-tour participant, Switzerland uses red only where there is a history of crashes — leading to inconsistency in the message because crashes happen for different reasons. In the following example, colored pavement indicates a place of refuge from motor traffic — quite the opposite of the conflict zone in the previous Swiss example.

Who is the message of colored pavement supposed to be for? Bicyclists? Motorists? Both? Here it is apparently only for bicyclists.

Swiss use of colored pavement in non-conflict zone. Photo by Nicklaus Schranz.

Now let’s look at some US examples. The first common bike-lane color in the USA was blue, as used in Portland, Oregon. This bike lane in Cambridge, Massachusetts followed Portland’s example:

Cambridge, Massachusetts blue lane

Cambridge, Massachusetts blue lane

Blue led to objections, because it already had a designated use in the US vocabulary of colors: handicapped parking spaces.

Green was proposed instead, and it is on the way to become a standard. Unlike blue, it shows up under the monochromatic yellow-orange of sodium-vapor streetlamps as well as the blue-green of mercury-vapor lamps. Green markings are the subject of several experiments testing their use under various conditions.

Green bike lane in Seattle, Washington

Green bike lane in Seattle, Washington

Yes, experiments. To be included in the national reference, the Manual on Uniform Traffic Control Devices, and to be approved for general use, a new treatment has to be tested to see whether it affects behavior in an intended and desirable way. This is reasonable in the light of safety issues and expense. Where does it make sense to use paint; what consistent and understandable message might the paint send? What about durability of the paint; should it be reflectorized…there’s a tradeoff: reflectorized paint is slipperier. And so on.

Any state, city or town may install a nonstandard treatment and is exempted from legal liability if it works with the Federal Government and the National Committee on Uniform Traffic Control Devices, collects data and prepares a report on how the treatment worked.

Some communities don’t bother. Madison, Wisconsin has installed this crimson bike box. Crimson, even more than the European red, looks nearly black under both types of streetlights.

Red-painted bike box in Madison, Wisconsin. Madison Star-Intelligencer photo.

Crimson bike box in Madison, Wisconsin. Craig Schreiner/Wisconsin State Journal photo.

Madison, Wisconsin, of all places — a city with a long-standing and most knowledgeable bicycle program staff — one of the best in the nation. A city which has in the past known how to be innovative in ways that really work — see this example — and how to avoid costly and deadly mistakes.

Why the crimson bike box, then?

For many American bicycling advocates, trips to Europe take on the aura of a religious pilgrimage. Anything in Europe has to be better than what we do here, even if it isn’t.

As an aside: this reminds me of the American inferiority complex about European painting and music around the year 1900. American composers and artists who imitated European styles are largely forgotten today. We remember the American originals, who, certainly, adopted much from European styles, but who found their own voice. Scott Joplin. Charles Ives. George Gershwin. Duke Ellington. Aaron Copland. Bessie Smith, Billie Holliday, Ella Fitzgerald, Andy Warhol, Georgia O’Keeffe… but I digress.

It’s more than a question of an inferiority complex. It’s also about corporate lobbying. Bikes Belong, the bicycle industry’s political lobby, organizes its own scan tours. The goal of this lobby is to increase sales of bicycles — and why bother with troublesome, boring, nerdy details. Instead of sending professional program staff, Bikes Belong sends politicians. This is from the Bikes Belong Web site:

Zach [Vanderkooy] leads our project to make U.S. bicycling safer and more appealing by helping cities adapt the world’s best bike facility designs, policies, and programs inspired by leading bicycling cities in Europe.

And this is from a story on the Madison.com news blog:

The bike boxes are the first project from a European fact-finding tour of bicycle-friendly cities in Germany and the Netherlands that Madison Mayor Dave Cieslewicz, Dane County Executive Kathleen Falk and 19 other civic and business [leaders] made last month.

If you work for the bicycle program staff of a city, the Mayor is your boss, and you do what the Mayor tells you to do, or you can very well lose your job.

I wrote that before I learned of the following:

Arthur Ross, Madison’s long-time, nationally-recognized bicycle and pedestrian program manager, is being demoted — see this story.  Whether it has to do directly with the crimson bike box or not, I don’t know yet.

I’ve said it before: in planning for bicycling, we need to do better than the Europeans. Certainly so on the issue of painted pavement, because, clearly, Europe doesn’t use it in any consistent or logical way. We need to do better with other, similar issues too, and because we face bigger and different challenges — and because it would be very unfortunate to lose the opportunity to do better.

In its turn, Europe may learn from us too.

Streetcars and bicycles

The rails for the E line branch of the Green Line subway/streetcar in Boston, Massachusetts, USA occupied the middle of two-lane Centre Street for over 20 years after service was discontinued. There had been a proposal to redo the street and restore streetcar service, but ADA requirements for wheelchair compatibility would have required new tracks to snake over to raised platforms at the curbs for stops. Bicyclists, who already were crashing on the existing rails, would have had to cross the new rails repeatedly. Bus service with the transfer to the Green Line on Huntington Avenue, which runs in the median, is about 2 minutes slower than streetcar service. Reconstructing the street with the new rails also would have been very expensive. Eventually, the proponents for bus service won out and the old tracks were paved over.

The three remaining streetcar lines in Boston all run in the median. A busway also can run in the median. All conflicts can be addressed with signalization. But this solution requires a wide street. If it isn’t wide enough then you lose the bike lane/wide outside lane: here is an example.

A streetcar line on a one-way street allows bicycle traffic to stay on one side and streetcars on the other. Here’s a photo of this treatment in Portland, Oregon. It still has problems described in the caption. Or the streetcar may go contraflow with no other contraflow traffic allowed.

Not so good: Running the bikeway behind the trolley stop. A Copenhagen study found that running a cycle track behind a bus shelter led to 19 times the crash rate and 17 times the injury rate of other installations. Problem with a streetcar line, though, is that the tracks pose the risk of bicyclists’ crashing even when there is no streetcar nearby. That leaves no good solution other than to put the streetcar and bike route on different streets. Here’s an example of a bikeway behind a bus shelter from Portland. Unfortunately, the street here leads to an important river crossing, so a different bike route wasn’t an option.

I have heard that Phoenix’s new light rail system has to skew between stops either side of a one-way street because there is an important trip generator on the left side. A bike lane plays hopscotch with the light rail line and bicyclists must cross the street twice to continue. At least it is possible to transport bicycles in the light rail cars — probably the best way to get through that area with a bicycle!

Portland, Oregon HAWK Beacon

What is a HAWK beacon?

A High-intensity Activated crossWalK beacon, or HAWK beacon, is much like the flashing lights commonly used to stop traffic at fire stations and railroad crossings — but applied to a crosswalk. The HAWK beacon is dark unless a pedestrian’ pushes a button to cross. Three reasons commonly given for using a HAWK beacon are:

  • A traffic signal that is normally green or that turns red when nobody needs to cross may not be as effective in stopping cross traffic;
  • There is no need to have an active signal unless someone actually wants to use the crosswalk
  • The HAWK beacon has a flashing red that follows the steady red. Traffic may restart if pedestrians have finished crossing, reducing delays. Continue reading

Hawthorne Bridge discussion gets thorny

Riding a bicycle on a sidewalk is rarely a better choice than riding in the street, but it is better on the Hawthorne bridge in Portland, Oregon, which has a narrow roadway with a treacherous steel-grid deck.

I first rode across this bridge in 1987. As of my more recent exploration of the bridge in September, 2008, the sidewalks have been widened significantly, and the routes to and from them greatly improved.

My friend Kat Iverson rode behind me with her helmet camera and shot the 5-minute video which you may view here.

More recently yet, I have read a blog posting by Mark Stosberg about the bridge. He and I agree that riding on the sidewalk is a necessary evil in this situation. He even links to my Web site as a reference. He states correctly that there are “no roads or driveways to cross on the bridge while traveling westbound.”

But just about there, my agreement with him begins to fade.

Continue reading

Bike box rationales

On another Web page, I have discussed the features and operational characteristics of so-called “bike boxes”, in which bicyclists wait for traffic signals ahead of the stop line for motor traffic. I recommend that page as background information for this discussion.

In this posting, I will discuss rationales advanced for the installation of bike boxes.

There are two principal rationales for a bike box, one of which I regard as valid but which might better be served by a different implementation. The other rationale, I find very distressing.

The first rationale is to accommodate a high volume of bicycle traffic, where bicyclists might have to wait through multiple signal cycles behind motor traffic, or else might filter forward and then not have room to wait. I recommend that bicyclists wait behind the first motor vehicle, so as not to be caught on the light change, and to negotiate with the driver of the second vehicle in line. That places the bicyclist in the exhaust of the first vehicle, but that’s better than risking a right hook collision. The exhaust problem has become far less serious in countries which have mandated pollution control on motor vehicles. But — there’s only so much room behind the first vehicle for a couple of bicyclists. A bike box behind the first vehicle would formalize that option, but unfortunately, the length of vehicles varies.

A bike box is advantageous in terms of bicyclists’ travel time when going straight through the intersection, if it facilitates filtering forward past stopped traffic — though, on the other hand, it increases motorists’ travel time. The bike box makes no significant difference in a bicyclist’s through travel time when the bicyclist arrives on the green.

But a bicyclist can get caught at the right side of the roadway when approaching the bike box, and the light turns green. Merging into the flow to go straight, or make a vehicular left-turn, is more advantageous unless traffic is very congested. (And that’s one reason among others that use of a bike lane should not be mandatory!)

The other rationale for a bike box is to encourage more people to ride bicycles by increasing comfort. I find this rationale very scary when the supposedly comfortable facility includes a deathtrap. I call this the “Pied Piper” approach to bicycle planning. It involves some convoluted thinking — bicyclists fear motorists, so, build facilities which appear less scary to the bicyclists.

A bike box with a pre-green signal interval (red and yellow in European practice) provides a warning for a bicyclist not to overtake and swerve in front of the first motor vehicle waiting at the intersection as the light turns green. He/she can still get stuck waiting for through traffic to clear, and the signal to turn red, then green again, if the intention using the bike box was to prepare a left turn (as with a Vancouver, BC bike box and some in New York City) or to cross to the other side of a one-way street (as with a bike box in Eugene, Oregon).

Motorists waiting behind a bike box without the pre-green are expected to look for bicyclists in their right rear-view mirror while also scanning the intersection ahead. That increases the likelihood of mistakes in both tasks, but also, the right rear-view mirror doesn’t provide complete coverage of the area where a bicyclist may be, particularly for the driver of a truck or bus with a high cab and a hood. If the motorist doesn’t look into the mirror at the right time, the bicyclist may have passed outside the field of view seen in the mirror. That is the rationale for additional mirrors, beepers, bicyclist-presence actuated flashers etc. that have been proposed to warn motorists of bicyclists overtaking on the right, and warn bicyclists of motorists preparing to turn right — none of which measures have been implemented in practice and all of which are technological solutions, with the attendant problems of implementation rollout and reliability.

So: what to recommend? here’s what I suggest. Never overtake a long truck or bus with less than 5 feet of clearance to its side, not even in a bike lane. Preferably, overtake on the left or move forward in line with other traffic, but in a traffic jam, you may filter forward *slowly* in a bike lane. Be aware of thehazard of car doors opening from either side, pedestrians stepping out form in front of tall vehicles, etc. Never swerve across in front of a vehicle unless you can be entirely sure that it will not start to move. Make eye contact with the driver, signal your intentions. If you can’t see the driver in a high-cab vehicle, just don’t swerve left. Pulling into line behind a vehicle that is waiting for a traffic signal or stop sign is reasonably safe if you obey these precautions. Swerving across in front of a vehicle waiting first in line, even with a bike box, is only safe if you can be sure that the traffic signal is not about to change.

Alternatives to the bike box?, For less-skillful bicyclists in urban areas, I favor the bicycle boulevard concept, in which bicyclists and motorists share a roadway according to the normal vehicular rules of the road, on a street with low traffic volume — typically, a residential street paralleling an arterial, using diverters and small traffic circles to keep down the volume and speed of motor traffic. This approach avoids the problems with attempting to accommodate conflicting movements with special facilities on a street that also carries heavy motor traffic. There are tradeoffs, to be sure: the bicycle boulevard isn’t a main street, so it may not provide such a direct route between as many trip endpoints — and unless bicycle transportation is taken very seriously, the bicycle boulevard may not have as favorable signalization as a main street. I have seen and ridden bicycle boulevards in Berkeley and Eugene, and they do seem to work rather well in those cities. No, I don’t have use or crash data, only my personal observation.