Talk:Segregated cycle facilities

Kenneth D. Cross Study

This is my first attempt at using the talk page...please forgive any errors in formatting as I muddle my way through....

The current section titled Evidence Against states the following, "In the 1970s the California Statewide Bicycle Committee arranged with Kenneth D. Cross for a study of car-bike collisions, expecting that this study would support their arguments on collision prevention. When presented to the Committee in Sacramento on 19 June 1974, Cross's study showed the opposite: only 0.5% of car-bike collisions had occurred between straight-ahead cyclists and overtaking straight-ahead motorists.[37] Cross later had a contract with the National Highway Traffic Safety Administration (NHTSA) to produce an improved study (on a pseudo-random national sample), and the results were much the same.[38]"

In the Kenneth Cross Study, various collisions were categorized. Type 13 is listed as follows (paper here: http://ntl.bts.gov/lib/25000/25400/25439/DOT-HS-803-315.pdf):

"Problem Type 13 (24.6% Fatal; 4.0% Non-Fatal) Problem Type 13 must be considered one of the most important problem types revealed by this study, because it accounted for nearly one-fourth of all fatalities in the sample--three times as many as any other problem type.The distinguishing characteristics of this problem type are (a) the motor vehicle overtook and collided with a bicycle traveling in the same direction as the motor vehicle, and (b) the collisions occurred because the motorist failed to observe the bicyclist until the accident was imminent.The distinguishing characteristic of Problem Type 13 is that the operator of the overtaking motor vehicle failed to observe the bicyclist until the vehicles were in such close proximity that successful evasive action was impossible."

... This is the second paper by Cross which purportedly had the same results as the first paper (per the original wikipedia entry). The excerpt above is from the second paper. Upon reading the results of Type 13, the most dangerous type of car-bike collision resulting in fatality was a result of same direction overtaking.

...

So the section stating that the Cross study proved that same-direction traffic was responsible for "only 0.5% of car-bike collisions had occurred between straight-ahead cyclists and overtaking straight-ahead motorists" is incorrect.

The section linking here: http://www.johnforester.com/Articles/Safety/Cross01.htm was also deleted because the data presented did not match what was summarized on wikipedia nor was it part of the second Cross study. I was unable to find exactly how the numbers here: http://www.johnforester.com/Articles/Safety/Cross01.htm were derived from the Cross study.

Additionally, the percentages on Forester's page do not match the percentages on the Cross study. The problem types on the Forester page do not match the Cross study. ...

Hope this clarifies the reason for deleting the section.

What is the next step?

Edit: Should a page be made for the Kenneth Cross Study, so that it can be linked to?

(Mightybeancounter (talk) 06:22, 26 October 2011 (UTC))

Yes, the 0.5% assertion does not appear to be supported by the cited source. But instead of deleting the section entirely, let's try to rewrite it in a way that is supported by the sources. --Born2cycle (talk) 17:11, 26 October 2011 (UTC)

(Born2cycle](talk) 17:11, 26 October 2011 (UTC))

So the assertion that there is evidence against separated bicycle infrastructure was initially put forth by John Forester, per the original article. I'm unclear on how the section would be rewritten without acknowledging Forester's deletion of the Cross results. Would that need to be explained? I've proposed edits.

The original stated this:

"In the 1970s the California Statewide Bicycle Committee arranged with Kenneth D. Cross for a study of car-bike collisions, expecting that this study would support their arguments on collision prevention. "

"Cross later had a contract with the National Highway Traffic Safety Administration (NHTSA) to produce an improved study (on a pseudo-random national sample), and the results were much the same.[38]"

How do we know that the reason for the study was to support the Committee's arguments? From the Cross paper on the reason for the study, I've found the quote "to determine the causes of bicycle/motor-vehicle accidents and to use data on accident causation to identify potential counter-measure approaches." I propose the following change:

In the 1970s the California Statewide Bicycle Committee arranged with Kenneth D. Cross to determine the various types of bicycle/motor-vehicle accidents and to use the results of the study to determine potential countermeasures.

The original stated this:

When presented to the Committee in Sacramento on 19 June 1974, Cross's study showed that the opposite: only 0.5% of car-bike collisions had occurred between straight-ahead cyclists and overtaking straight-ahead motorists.[37]

My proposed edit will be:

When presented to the Committee in Sacramento on 19 June 1974, Cross's study showed that the most dangerous type of collision was what was categorized as Problem Type 13 consisting of 24.6% fatalities and 4.0% injuries. Cross identified this as one of the most dangerous types of collisions as it accounted for nearly "one-fourth of all fatalities in the sample--three times as many as any other problem type". The defining characteristic of this type of collision "(a) the motor vehicle overtook and collided with a bicycle traveling in the same direction as the motor vehicle, and (b) the collisions occurred because the motorist failed to observe the bicyclist until the accident was imminent."

Although the Cross Study has been used by Forester to argue against separated infrastructure, the Cross study proved that the public fear of rear-end collisions caused by same direction traffic was substantiated. — Preceding unsigned comment added by Mightybeancounter (talk • contribs) 19:35, 26 October 2011 (UTC)

Okay, I've taken a closer look. The article references the first Cross Study.

Table A of that study shows ten "Accident Types", labeled A-J. Accident Type F is "Motorist Collided With Rear of Cyclist" and is shown to have a relative contribution of 4.17% (of all the car-bike collisions studied, a motorist collided with the rear of the cyclist in 4.17% of them).

This Accident Type is discussed in more detail in a section labeled, "Motorist Collided with Rear of Cyclist". In that section it illustrates the five sub-types of this Accident Type in Figure 10, and notes, "The five sub-types shown in Figure 10 constitute only 4.1 percent of the total accident sample." Each of the five sub-types shown in Figure 10 is accompanied by a percentage indicating the relative contribution of that sub-type to the total 4.1% relative contribution of this Accident Type (the percents in this Figure are 43, 25, 6, 13 and 13, adding up to 100%... 100% of 4.1%).

Of the five sub-types of this Accident Type, one represents those crashes away from intersections in which the cyclist and motorist are both going straight, and the relative contribution of this sub-type is labeled as being 13% of this type. 13% of 4.1 is 0.533% of all car-bike collisions in this study, which seems to substantiate the statement in the article: "Cross's study showed the opposite: only 0.5% of car-bike collisions had occurred between straight-ahead cyclists and overtaking straight-ahead motorists".

The study also refers to the frequency of this type of accident as "occurred extremely infrequently":

Accidents in which the motorist collided with the rear of the bicyclist occur relatively infrequently. The five sub-types shown in Figure 10 constitute only 4.1 percent of the total accident sample. This is surprising since these types of accidents appear most hazardous to the bicyclist. Most bicyclists would predict that many accidents occur when a bicyclist is riding along a heavily trafficked street-with a line of parked cars along the right-hand curb. In fact, this type of accident occurred extremely infrequently in our sample.

The second Cross Study classifies crash types differently, so I don't know if we can glean a comparable figure out of it. It seems that a large proportion of those Type 13 crashes (motorist overtaking; bicyclist not observed) occurred at night with the cyclist having inadequate lighting. In particular, Table 36 shows that while 25.2% of all fatals were of Type 13, 17.4% (or 69% of all of Type 13) occurred at nighttime (9.0% rural nighttime + 8.4% urban nighttime). Daytime Type 13s account for only 7.1% of all fatals. Considering that the total number of fatals is only a fraction of all bike-car crashes, I think that indicates the 0.5% is in the right ballpark per this study too.

In any case, I see nothing here that supports our saying, "the Cross study proved that the public fear of rear-end collisions caused by same direction traffic was substantiated".

By the way, bicyclinginfo.org says that in 2009 there were 630 bicyclist fatalities in the U.S., and 51,000 bicyclist injuries. Even if we include the nighttime crashes involving inadequately lighted cyclists, that means about 25% of those 630 fatalities, or about 158, were Type 13. In other words, if you're an average cyclist and you're in a bike crash, the odds that you'll be killed in a from-behind crash while both you and the motorist are going straight is about 158 out of 51000 or... 0.3%. I think this suggests, especially if poor lighting at night is eliminated as a factor, that concern about other types of crashes, those involving turning and crossing movements, should be given much higher priority. --Born2cycle (talk) 00:37, 27 October 2011 (UTC)

The discussion confounds the two Cross studies, the first done for California, the second for the NHTSA. The first study has collision types designated by letters, the second has collision types designated by numbers. It is inappropriate to compare the data from one study with the conclusions of the other study, which appears to have been done. The entirely incorrect statement is that the first Cross study showed that 38% of car-bike collisions occurred between straight-ahead cyclists and straight-ahead motorists. The correct value, for the first Cross study, is 0.5%, as the commenter immediately before, or the one before that, had concluded. This major error requires correction as rapidly as possible, as the erroneous value has been circulated (which is how it came to my attention). The statement that California government expected that this first Cross study would support their bikeway program being imposed on cyclists is correct. That is why they had Cross make his presentation in a room at the Sacramento airport, where many officials would be present. They were utterly confounded when that study strongly disproved their hopes and all their program, which is why they then hid the study. I was there, and I saved my copy, which is why I could publish it on my website, johnforester.com, where the Wikipedia author found it. How that author concluded 38% for the correct proportion is outside my knowledge. John Forester (talk) 00:58, 19 March 2013 (UTC) John Forester

Inline galleries

In it's current version the article has two inline galleries. One in the Segregating cyclists controversy section (five items) and one in the Bikeways that use independent rights-of-way section (12 photos). WP:IG states that One rule of thumb to consider: if, due to its content, such a gallery would only lend itself to a title along the lines of "Gallery" or "Images of [insert article title]", as opposed to a more descriptive title, the gallery should either be revamped or moved to the Commons. From my point of view the two current galleries does very little more than that. The latter gallery basically shows the same, but simply at different locations. The first shows a number of signs and one (relevant) photo of an "ill" parked truck. I don't think that the galleries contribute a lot to neither those sections, which isn't illustrated with one image and therefore I suggest that they are deleted and one image is left in each section. --Heb (talk) 10:56, 22 May 2013 (UTC)

Good point. I've started putting them into proper galleries at least, instead of lists of images some of which don't illustrate the sections. A next step would be to trim down the number of images. WP:IG suggests putting the images into Talk so I'll do that if I remove any. Nubeli (talk) 12:24, 8 January 2015 (UTC)

This image would be better in Cycling infrastructure rather than here since it doesn't match any of the types:

• 
  This diverter forces motor vehicles to turn, and allows through passage for bicyclists and pedestrians.

Nubeli (talk) 12:34, 8 January 2015 (UTC)

Segregated motorcycle facilities

Can the idea of converting segregated cycle facilities to segregated motorcycle facilities be mentioned ? Should be useful if the motorway is converted to a bicycle boulevard as both then complement each other perfectly. 109.130.233.118 (talk) 17:40, 30 May 2014 (UTC)

"On road: cycle track" ?

In this official presentation on road it is a cycle lane, next to roadway a "cycle track".--Ulamm (talk) 22:57, 16 November 2014 (UTC)