Engineering - Page 5 of 5

Bicyclist Behaviors & Crash Risk

December 20, 2012/17 Comments/in Engineering/by Dan Gutierrez

Successful bicyclist behavior is driven by knowledge of common crash types and the behaviors needed to successfully avoid those crash types. Bicyclist behavior comes in a spectrum with three main behaviors, and in this article we aim to briefly describe the spectrum and show how those behaviors fare in common crossing conflict crash scenarios with diagrams and supportive video.

There are three types of bicyclist behavior:

Pedestrian behavior
Avoiding the roadway by using paths, sidewalks/crosswalks, often against traffic flow

Edge behavior
Operating at the roadway edge or close to parked cars, includes shoulder and edge bike lane use

Driver behavior
Following the rules of the road by using roadway through lanes and turn lanes as an equal driver

The behavior descriptions above meant to describe behavior at a particular place and time, not people, since a cyclist for example who prefers to engage in driver behavior on normal roads, may be required by law to engage in edge behavior in an edge bike lane. When operating on a crowded shared use path that is away from roads, with high pedestrian volumes, that same cyclist who would prefer driver behavior, may have no choice but to use ped behavior to avoid crashes. So it is not uncommon for cyclists to engage in multiple behaviors on a single trip.

This is why we don’t talk of edge cyclists, though a cyclist may be edge riding on a particular facility, and similar for driver and ped behavior. It is also important to understand that unlike edge and ped behavior, driver behavior is a learned behavior that must be taught; it is not innate. So just because a bicyclist who may at present prefer the more common edge or ped behaviors, does not mean that they will never learn driver skills and/or engage in driver behavior, so we recognize that behaviors are not in general fixed and can change over time and exposure to skills training.

The value in identifying behavior, instead of cyclists themselves, is its descriptive power in identifying how behavior influences crash likelihood and why some behaviors are more successful than others in an urban environment with driveways and intersections, the places where most cycling crashes occur. The most common types of crashes are referred to as crossing crashes, where the paths of a turning motorist at a driveway or intersection and a straight through cyclist can potentially cross, creating conflicts and crashes. Because of this, we often refer to driveways and intersections as crossing conflict areas.

The pie chart couplet (right) shows that even though car-bike crashes comprise the minority of cases where bicyclists hit the ground, when expanded to a full pie (at the right side), the crossing crashes comprise about 5/6 of the total number of crashes. In examining these crossing crash types, we can learn a great deal about behavior and the facilities and laws that enable or restrict behaviors, influence how successful cyclists will be at negotiating urban roads.

Crossing Conflict Types

Let’s examine the three main crossing conflict types and the effect of bicyclist behavior. The three types are pullout, left cross and right hook. These conflicts occur at driveways and intersections. We’ll examine each individually.

Pullout

(shown in the diagram at a driveway)

A pullout occurs when a motorist leaves a driveway or turns right at an intersection and approaches a cyclist from the right side, perpendicular to the cyclist’s through line of travel, resulting in a side impact to the cyclist, or causing the cyclist to hit the side or rear of the vehicle if it turns sooner in front of the cyclist.
Look at the driver of the silver SUV approaching the driveway, prior to making a right turn into the street. The driver is mainly looking to the left for road traffic, such as cars and trucks, so a bicyclist using driver behavior is more easily seen (visibility) by the SUV driver because they are operating where drivers pulling out of driveways are expecting approaching traffic to be located in the roadway. In addition, that same bicyclist can see further down the driveway (vantage) and determine when a motorist is preparing to make a right turn. Visibility and vantage go hand in hand when a bicyclists is further leftward in the roadway.

A bicyclist using edge behavior is not where motorists expect cyclists to be, and may be visually shielded by fixed sight line obstructions such as foliage, and street furniture, or even dynamic obstructions such as peds. Thus a motorist may not see a bicyclist at the edge and turn in front of them. An even more difficult dynamic occurs when bicyclists are on the sidewalk engaging in ped behavior. Here they not where motorists are expecting them to be (in the road), and are even more susceptible to visual screening by fixed and dynamic obstructions, so they have minimal visibility and vantage; the opposite of the driver behavior case.

Now we need to consider that motorists about to exit a driveway or turn at intersections also look to their right. They use this alternate scan to look for slow moving, about 2-3 mph peds on the sidewalk. They are not expecting or looking for much faster bicyclists facing traffic on the sidewalk, or the illegal bicyclists riding facing traffic at the road edge. So these “backwards” edge and ped behaviors have even poorer visibility and vantage than their normal flow counterparts. Notice also that there is no “reversed” driver behavior, driver behavior skills classes teach cyclist to never operate this way.

It should come as no surprise that bicyclists are more frequently injured by pullouts when operating on the sidewalk or at the road edge. These behaviors are less successful than driver behavior in negotiating driveways and intersection pullouts.

In the tabs below are video clips showing pullout scenarios.

[tabs slidertype=”top tabs”] [tabcontainer] [tabtext]Video Example 1[/tabtext] [tabtext]Video Example 2[/tabtext] [tabtext]Video Example 3[/tabtext] [/tabcontainer] [tabcontent] [tab]

An edge rider passes stopped traffic on the right to pass a motorist about to leave a driveway.

[/tab] [tab]

This clip shows a driveway pullout hazard from a blind underground driveway. In this video it was clear that poor vantage and visibility from ped behavior can increase bicyclist exposure to pullouts.[/tab] [tab]

In this clip, we have one more example of a bicyclist trying to ride at normal traffic speed on the sidewalk to pass slower traffic in the road, and still dodge cars waiting to pull out as well as street furniture like a newspaper box.[/tab] [/tabcontent] [/tabs]

Left Cross

Happens where a cyclist is making a through movement and an oppositely directed motorist makes a left turn in front of and across the bicyclists’ line of travel.

Again we see that a motorist waiting to make a left turn at an uncontrolled crossing, has a clear view of a bicyclist using driver behavior, and a progressively more difficult time seeing bicyclists using edge or ped behavior in the direction of traffic, since they can be lost in visual chatter at the road edge, including street furniture, foliage or even peds. Here again we find that driver behavior gives the best visibility and vantage to cyclists approaching a crossing conflict area. For cyclist on the sidewalk, or even in the road, they are approaching from a direction behind the left turning motorist, and in their blind spot, so neither the bicyclist nor the motorist in such a “left hook” (the mirror image of the “right hook”, the next crash we cover) crash see each other until just before contact since the visibility and vantage are both very poor.

The tabs below contain video examples of left cross and left hook conflicts.

[tabs slidertype=”top tabs”] [tabcontainer] [tabtext]Video Example 1[/tabtext] [tabtext]Video Example 2[/tabtext] [tabtext]Video Example 3[/tabtext] [/tabcontainer] [tabcontent] [tab]

Even a left turning bicyclist using driver behavior may left cross another bicyclist who is engaging in ped behavior on the sidewalk, since the visibility of the sidewalk bicyclist approaching the crosswalk is very poor.[/tab] [tab]

And here is another case where a fit female cyclist is screened by stopped traffic in the travel lanes, and because of this neither she nor the motorist turning left could see each other approaching. While the motorist is legally at fault for not yielding, the cyclist could not see far enough ahead at her speed to stop in case motorist did make an ill-advised turn across her path.

In the above video the lesson is that facilities that enforce edge behavior often create poor visibility/vantage crossing conflicts, compared to encouraging driver behavior.[/tab] [tab]

And finally we show a video of a cyclist riding facing traffic to demonstrate the difficulties when cyclist ride facing traffic, on either the sidewalk or in the roadway.[/tab] [/tabcontent] [/tabs]

Right Hook

The last crossing crash type we will examine in terms of behavior is the right hook, which is the most frequent cause of car-bike crashes, and leads to many bicyclist fatalities.

The classic right hook crash comes in two varieties; a bicyclist riding near the edge (edge behavior) is passed close to the intersection by a motorist traveling in the same direction, who then proceeds to turn right in front of the cyclist, cutting her off and causing a crash. In the other the bicyclist approaches a motorist stopped at the intersection waiting to turn right and tries to pass on the right (edge behavior again) as the motorist starts their turn. In the first case the motorist is at fault for turning in front of another moving vehicle, in the second, the cyclist is at fault for passing a right turning driver on the right, though drivers often “help” the cyclist make the mistake by not driving close enough to the edge to preclude passing by cyclists on the right. These scenarios can be seen in the lower right of the image below:

In a similar way, a bicyclist on the sidewalk can be hooked by a motorist, or ride into the path of a right turning motorist. In contrast a bicyclist engaging in driver behavior, by riding in the center of the travel lane, discourages motorists from passing on the intersection approach, thus precluding the first type of right hook where the motorist passes close to the intersection. Driver behavior also avoids the second type by allowing the cyclist to either wait behind the motorist stopped to make a turn, or to pass the stopped motorist on the left, thus successfully staying away from the crossing conflict. Engaging in edge or ped behavior is much like driving a motor vehicle, such as a sedan, inside the turn of a large truck, which is why the yellow sticker at the top is often placed on the rear of large trucks. The same issue, scaled down, is also true for bicyclists engaging in edge behavior, riding inside the turn of a much larger motor vehicle, so we ask cyclists to imagine that the lower sticker was on the back of every car.

Look to the left side of the diagram, which is the case for bike lanes. Bicyclists often edge ride and stay in the bike lane on the intersection or driveway approach, even though the law allows them to exit bike lanes to avoid crossing conflicts by using the more successful driver behavior, and right turning motorists often stay to the left of the bike lane instead of merging into it as is required by law (bike lane is part of the roadway and right turns are to be mad from as close as practicable to the curb or edge of the roadway). Taken together, these behaviors tend to manufacture crossing conflicts where motorists are allowed to make right turns on roads with typical minimum standard bike lanes. The image to the right is a California example photo showing that motorists and bicyclists often cooperate to create intersection conflicts when bike lanes are present.

And now we give some video examples in the tabs below.

[tabs slidertype=”top tabs”] [tabcontainer] [tabtext]Video Example 1[/tabtext] [tabtext]Video Example 2[/tabtext] [/tabcontainer] [tabcontent] [tab]

This video shows an edge behaving bicyclist passing on the right in a faded bike lane and luckily the motorists, who didn’t merge into the bike lane to prevent such right side passing, didn’t turn into her. The bicyclists using driver behavior had nothing to fear, since they were not in the conflict zone.[/tab] [tab]

This video shows a ped behaving bicyclist entering the crosswalk in front of a driver turning right. The bicyclist didn’t look to the left, where the threat originated. Shows that ped behavior can be problematic at intersections, especially when the threats are ignored.
[/tab] [/tabcontent] [/tabs]

Avoiding Conflicts: Driver Behavior

Next we show how driver behavior allows bicyclists to successfully avoid crossing conflicts.

The tabs below show video examples of conflict-avoidance through driver behavior.

[tabs slidertype=”top tabs”] [tabcontainer] [tabtext]Video Example 1[/tabtext] [tabtext]Video Example 2[/tabtext] [tabtext]Video Example 3[/tabtext] [/tabcontainer] [tabcontent] [tab]

In this example, the bicyclists are approaching a complicated intersection with preceding driveways, and transition from lane sharing (more like edge behavior) to lane control (driver behavior) near the intersection to discourage pullouts and right hook turns:[/tab] [tab]

Here we show how a merge from edge to driver behavior avoids a pullout conflict.[/tab] [tab]

Here we compare a manufactured engineering conflict of combined edge/ped behavior versus driver behavior in side-by-side fashion.

In the right side video, the designers try to force the cyclists to engage in ped behavior, and this puts them at a severe disadvantage at the uncontrolled ped crossing (crosswalk). Compare how long it took for the cyclists on the right to reach the same place the cyclists on the left reached by using the more successful driver behavior.[/tab] [/tabcontent] [/tabs]

In summary bicyclists are more successful when they understand driver behavior, since it is often the only successful way to negotiate intersections and driveways, by ensuring that they are seen by traffic and can see traffic (visibility/vantage). Special facilities that force ped behavior prevent the types of leftward merges that allow bicyclists to transition from edge to driver behavior on approaches to crossing conflict areas.

In our next article we will describe how road and bikeway facilities interplay with the behaviors and crossing conflicts, as well as some of the parallel movement hazards. We will show how engineering designs and traffic controls can support successful behaviors, and not discourage or prevent bicyclists from employing them.

The Enforcement of Imaginary Laws

December 19, 2012/1 Comment/in Enforcement/by Keri Caffrey

This story was originally published on CommuteOrlando, January 26, 2010. It has been updated here.

The Judge Mirandizes us as a group, then brings us forward one at a time to hear our plea, and the setting of a bond, etc. Those of us waiting are close enough to hear most of what is said.

When I approach his raised dais, he opens a folder, and then looks up in surprise. He says, “Are they serious? Operating a bicycle on the roadway?”

And as absurd as it sounds, my friend ChipSeal went back to jail that same night, arrested again on his way home from jail for operating on the roadway. What an incorrigible scofflaw! Read his story, beginning with While Minding My Own Business… I have great admiration for his gracious attitude toward those who detained him unfairly.

The right to travel by human power

ChipSeal’s case is a clear violation of his civil rights. The charge is unsupported by TX statute, and yet he was convicted of reckless driving and sentenced to time served (20 days).

When Eli Damon encountered an officer who didn’t want him on the roadway, he found himself charged with disorderly conduct. Eli maintains that he was calm and courteous in the encounter, but the officer was angered by his assertion that he was riding legally. The charge was prosecuted for four months before the prosecutor dropped it a week before the scheduled trial. You can read Eli’s story here.

In 2009, Bob Mionske covered the story of Tony Patrick, who was tasered and arrested for disorderly conduct in Chesapeake, OH for refusing an unlawful order to get off the road. His lawyer, Steve Magas, has more links to the story and the judge’s dismissal of charges here.

Being arrested for asserting your right to drive your bicycle on the road is an extreme violation of civil rights. But living under the specter of choosing between riding unsafely to avoid hassles and risking constant citations is also a violation of your right to travel by human power. In 2009, Fred U. experienced this in Port Orange, FL. The harassment ended when his lawyer got pretrial dismissals of all of his citations. Fred provided documentation for other cyclists who might face a similar predicament.

Cultural bias can be blinding

Nowhere is the bias more glaring than when an officer pulls a cyclist over for using one lane on an empty six-lane road on a Sunday morning. Then, during the stop the officer repeatedly asserts that the cyclist is failing to share the road by not riding at the far right of that lane. This might raise the question, with whom exactly is he failing to share the road? (See Red & Blue in the Rear View… Again?)

A few months ago, Mighk Wilson was pulled over for riding in one of three lanes on South Street. This is a one-way street, downtown, with a 30mph speed limit and plenty of traffic lights to prevent movement anywhere near that fast. Of course, when there are lots of motorists, traffic moves slower still. Agitated with Mighk’s knowledge of traffic law, the officer huffed that he was “one of those people who just doesn’t care about others.”

Bias denies basic human equity to its target. Bias is impervious to logic and reason. Bias is blind to its own absurdity, no matter how glaring. As much headway as we’re making with law enforcement, stubborn anti-cycling bias can still be encountered among the ranks of the most enlightened department.

These stories are infuriating to transportation cyclists in particular, but they cut even deeper for those who are car-free. When the cops are lying in wait for a cyclist who must pass through their jurisdiction, they are essentially violating that person’s right to use a public utility. By insisting, under threat of arrest, that a cyclist ride in a place not required by statute, these officers are abusing their authority.

Strategies for the chance encounter

Prompted by an Ask Geo email, I thought it might be a good idea to collect some wisdom on how to deal with uninformed police officers. I have not been pulled over or otherwise hassled by any of the many, many police officers who have passed me in my metro area travels. My interactions with them always consist of a friendly wave. But I know others who have been pulled over or ordered over the public-address system to ride far right. So I wondered, what’s the best way to conduct myself in a traffic stop? And how would/should I handle an officer giving me an unlawful order over his PA?

The unwarranted traffic stop

I think Richard Moeur’s story is exemplary in both his handling and its outcome. I got several good take-aways from it:

Ask the officer’s intentions. Find out what he is requesting (ride on the sidewalk, ride on the edge of the road, ride on a different road).
Resist the urge to discuss the law right away, and ask for a name and badge number.
If the opportunity arises, be armed with a copy of the statutes.
If the officer asks why you were riding where you were, present the pertinent talking points (know your talking points).

In my opinion, it’s better to not get a citation than to have to deal with one in court (even if you win). In the event that the officer does not respond favorably to your roadside defense, the best course may be finding a way to comply without compromising your safety, then deal with educating the officer via contact with the department.

The drive-by command

In the case of the cyclist who was told over the PA to get on the sidewalk, there is little recourse for dealing with the individual officer unless the officer stops. I’ve heard from several cyclists that deputies have told them over the PA to ride far right. This puts the cyclist in a predicament: comply and put her safety at risk (with no way to identify the officer); not comply and have an angry officer loop back around and pull her over; or flag the officer down and attempt to discuss it before he’s agitated by non-compliance.

There’s risk in that last option, too, depending on the officer’s attitude, as Brad Marcel in Tampa found out. When an officer ordered him to ride farther right in a narrow lane, he tried to flag her down to talk to her. She thought he’d flipped her off. He ended up receiving a citation and the officer has claimed that he was antagonistic (which he denies). In court the officer claimed he was impeding traffic (a statute which does not apply to non-motorized vehicles in Florida). He read the statute governing bicyclist lane position and explained that the lanes on road met the exemption of a “substandard” width lane because they are less than 14ft wide. The officer replied that no lanes in Tampa are 14ft wide, so that made no sense. The judge found him guilty.

So, I think Richard’s advice serves well here, too. If I could, I’d flag the officer down, ask him/her for clarification of the request and get a name and badge number. Depending on the officer’s demeanor, I might leave it at that and deal with unlawful demands higher up the chain of command.

Departmental bias

As far as I know, there are no systemic bias problems within any of the Orlando metro area police departments. As long as the source of the problem is an errant officer, it seems easiest to get the name and badge number and make nice till he goes away. Then I can deal with him through his supervisors. I also have the luxury of finding alternative routes and/or using my car until the situation is resolved.

Unfortunately, what ChipSeal and Eli are dealing with appears to be departmental. This was also the problem Fred encountered in Port Orange. He tried to go up the chain of command after the first encounter, to no avail. It took a swift pretrial dismissal of his citation to put a stop to his troubles. In the meantime, he faced harassment whenever he needed to travel through Port Orange to conduct business.

In December of 2009, Chipseal missed an appointment (after traveling a heck of a long way) because he was stopped three times for riding legally. We all thought that was over the top until he spent two nights in jail!

In one post, ChipSeal says

As it stands now, I am in under threat of arrest any time I travel, for slow vehicles like bicycles will, by their nature and in the strictest sense of the word, impede all other more powerful vehicles. How can I get to work? The grocer? Make appointments? Make any plans considering I could be jailed simply for using the public road? For leaving my driveway on a bicycle? Am I being subjected to a de-facto house arrest?

Eli’s saga is equally distressing. He’s been detained, had his bicycle confiscated and been arrested. His range of travel has been severely limited. He told me:

I have been on near virtual house arrest for the past several months. I am on bail because of the pending criminal charge so if I have another encounter, even with a different cop in a different town, before the case is resolved I could be put in jail until it is.

Of course, he’s learned a lot through his experience. Here’s some advice from him that I’ll keep in mind:

Know the law (of course).
If the officer asks for an explanation of your riding style, keep your answer concise (never too much information at once).
Use formal, respectful language and don’t interrupt.
“If the officer lets you go, do not ride away from the officer if you can help it. Let the officer leave first. You might have to walk to someplace that is a comfortable distance away but where you can still see the officer and wait awhile.”
A suggestion Eli plans to use with potentially volatile officers in the future: ask, “Are you going to write me a ticket?” It could potentially end the encounter quickly and prevent arrest. A citation is certainly less inconvenient than going to jail.
After the encounter, document everything that happened ASAP, contact appropriate authorities and assisting organizations. In Florida, contact George Martin.
Again, get the name and badge number. Get it first, before you get distracted!

George Martin offers similar advice in his Ask Geo post today.

Correcting the cultural problem

Ultimately, these incidents are a manifestation of the bigger problem — what Steve Goodridge describes in America’s Taboo Against Bicycle Driving. The problem must be tackled from a number of directions. We are working very hard to build a mutually beneficial relationship with law enforcement and to create a program that will give them knowledge of the laws and help them understand how we protect ourselves on the road. But law enforcement officers are a part of our general culture. They’re people. They’re just as influenced as anyone else by the biases of the society in which they live.

The fundamental rule of the road is First Come, First Served (FCFS). The distorted rule of the Culture of Speed is All life yields to faster traffic. When the roads are governed by FCFS, pedestrians and bicycle drivers are people using public roads. When governed by the Culture of Speed, they are merely objects in the way.

As has been noted before, the Culture of Speed causes some police to enforce traffic flow vs safety. Worse, they often don’t even realize that their concepts of protecting safety are stealthy manifestations of the Great Reframing. Almost 100 years ago, traffic engineers began to manage the steady flow of automobiles at the expense of non-motorized users. The notion that speed differentials and lane changes cause safety problems resulting from the presence of a slow vehicle rather than the incompetent or aggressive behavior of faster drivers is a result of 100-year-old propaganda campaigns which removed pedestrians and bicyclists from the roads by dissociating safety from behavior. This is why most people, police officers included, don’t realize their ideas of safety are so badly skewed.

With this understanding, my friend ChipSeal’s graciousness is not only admirable, it is necessary to solve the problem. We have work to do. We need grace, understanding and cooperation. And we need those in law enforcement to be our allies.

Since the original publication of this post in 2010, Chipseal was charged and convicted of reckless driving (for what was essentially defensive driving). Eli has continued to face harassment from police departments in two Massachusetts towns. He has won his court cases and filed a lawsuit against one police department. In Florida, Fred U has faced repeated harassment from several police departments. Each time, he has won in court, but it has cost him hundreds of dollars in legal fees — to defend defensive driving.

Achieving a Vision

December 14, 2012/7 Comments/in Education/by Keri Caffrey

Presentation at the Congress for New Urbanism 20 conference:

In the video presentation above, I explain the root cause of the beliefs that inhibit bicycling in America, why the prevailing strategy can’t fix it, and offer a strategy that can. In addition to teaching people to be successful anywhere, this strategy includes many progressive infrastructure ideas that are cost-effective, versatile, expandable and supportive of successful bicyclists.

For more on this topic:

Strategy for a Cyclist-Friendly Community by Keri Caffrey