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Old 09-13-10, 07:24 AM   #1
The Human Car
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(LTBL:Chap 2a) Those Bothersome Bumps From Behind

http://www.wright.edu/~jeffrey.hiles...ening/ch2.html

The kind of separation between cars and bikes provided by bike lanes and next-to-the-road bike paths helps keep motorists from bumping into bicyclists’ back ends. However, these facilities do little to prevent the numerous kinds of collisions caused by the crossing and turning movements of both bicyclists and motorists. Bikeway critics, therefore, question whether overtaking motorists are enough of a threat to justify the effort to separate bikes from cars, considering that there may be side effects, such as hindering bicyclists’ movements and making crossing and turning more difficult, or even more frequent. This chapter will put through the ringer what we know about bump-from-behind collisions in hopes of squeezing out a reasoned understanding of these controversial car-bike crashes. (For convenience, I will use “car” to refer to any kind of motor vehicle.)

John Forester (1994) argues that you can get a clear answer to the overtaking-risk question by looking at crash statistics:

Quote:
These show that many more car-bike collisions (about 95 percent) are caused by crossing and turning maneuvers from in front of the cyclist than are caused by the car-from-behind-a-lawful-cyclist collisions that worry cyclist-inferiority believers so much. Furthermore, car-bike collisions are only about 12 percent of all accidents to cyclists. This combination makes the car-overtaking-a-lawful-cyclist in urban areas in daylight (which is the type of accident used to justify transportational bikeways) only about 0.3 percent of total accidents to cyclists (pp. 10-11).
Kenneth Cross (1978), whose bicycle crash studies form the foundation for many of Forester’s arguments, paints what seems to be a different picture when he describes what he calls “Problem Type 13,” in which an overtaking motorist fails to see a bicyclist until it’s too late to avoid a collision:

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Although seven other problem types occurred more frequently than Problem Type 13, this problem type must be considered one of the most important because it accounted for nearly one-fourth of all fatal accidents in the sample—three times as many as any other problem type (p. 72).
So we have on the one hand an analysis that says the overtaking risk is negligible, and on the other hand an analysis that characterizes the overtaking collision as the most deadly of all car-bike crashes. A clearer picture emerges when we look more closely at Type 13 crashes and, first, at the study from which these statistics came.
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Old 09-13-10, 07:31 AM   #2
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Barry, modern arterial intersection designs with emphasized crossover zones, pocket lanes for thru bicyclists create more visible (IE towards road center, away from road edge) bicyclist road behaviors as a matter of course.

additionally, sharrow placement on class III bikeways approaching intersections can also lead bicyclists to better road visibility as would bike boxes and bike specific signals to place cyclists in a visible road and traffic position crossing intersections.

America is now in the 21st century, Barry. Arterial roadway and intersection design that accommodates vehicular cycling, destination positioning AND provides better lateral road position from bicyclists are already commonplace, codified in the MUTCD and the AASHTO design guide.

time to move beyond the feud, dontchyathink?
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Old 09-13-10, 10:01 AM   #3
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Right, and this is also in the specs:

http://maps.google.com/maps/ms?ie=UT...,266.49,,0,7.7

But you win and I give up any bike facility is a good facility.

(Mods you can lock or delete this junk.)
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Old 09-13-10, 10:05 AM   #4
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Barry - as far as i can reckon, thats would not be considered a bikelane, perhaps it is the old standard. to current specs, that's not a bikelane, thats a shoulder stripe.

you're deliberately misrepresenting bikeway design to try and prove a point. pretty lowbrow and very ideologue of you. if you have a map link that shows that road as developed for bikes with a class II bikeway at that location, i will stand corrected.

Your think your thread is junk because i post one rebuttal to the dated concerns of jeffery hiles?

Barry, you're the one posting 15 year old commentary on bike facilities and misleading examples of what you mischaracterize as a bikelane.

i do not agree that every facility is a good facility. luckily, the design guidance for the development of bicycle facilities has advanced significantly since 1996.

have you looked at your baltimore bike master plan and the design guidance contained therein? I thought you have been posting largely positive comments about the growing bikeways planning in your city.

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Old 09-13-10, 12:47 PM   #5
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The city does bike lanes and sharrows but everyone else basically only does shoulders to accommodate bicyclists, it's the latter policy that I have issues with. Shoulders are still a part of the design guidance as are door zone bike lanes.
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Old 09-13-10, 11:32 PM   #6
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"basically everyone else does shoulders to accomodate bicyclists" what? not in any bike master plan I'VE seen.......


time to move beyond the feud, Barry. its not 1996 anymore.
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Old 09-14-10, 05:09 AM   #7
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Best policy as rated by LAB: http://www.mdot.maryland.gov/Plannin...nts/FINALB.PDF

Percentage of State-owned roadway centerline miles with a bicycle level of comfort (BLOC) grade of “D” or better. (SHA)*
(That means shoulders only)

The original goal called for a 100 miles of "bike lanes" for the whole State of Maryland and no more for over the next 20 years.
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Old 09-14-10, 07:39 AM   #8
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boy, Barry- the state of marylands bike master plan you linked to is significantly more developed than simply 'adding 100 miles of bikelanes'.
55 percent of ALL roads in your state received a BLOS of C or better, dude!

time to move beyond the feud.

have you even heard of Class III bikeways?

There is nothing patently unsafe or unvehicular with shoulder use by bicyclists along high speed roads that have the shoulders improved for bicycle traffic. there is no conflict there with competent bicycling method.

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Old 09-14-10, 06:23 PM   #9
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boy, Barry- the state of marylands bike master plan you linked to is significantly more developed than simply 'adding 100 miles of bikelanes'.
55 percent of ALL roads in your state received a BLOS of C or better, dude!

time to move beyond the feud.

have you even heard of Class III bikeways?

There is nothing patently unsafe or unvehicular with shoulder use by bicyclists along high speed roads that have the shoulders improved for bicycle traffic. there is no conflict there with competent bicycling method.
55% of all STATE roads that lie in predominantly rural undeveloped areas and that percentage/mileage has not changed over the last 10 years nor is there any mechanism in place to change that. All our State roads are as good as they need to be in accommodating cyclists per this plan.

I am not trying to promote the feud but better considerations for cyclists then 50mph narrow two lane roads.
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Old 09-14-10, 09:42 PM   #10
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oh, better planning for bicyclists would come along with bikeway planning, regional and local bike master plans and implementation of road enhancements and a variety of bikeway treatment along corridors significant for bicycle traffic.

according to FHWA roadway design guidance, bicycle traffic should be considered as part of the transportation mix on all roads except those from which cyclists are prohibited.

I suspect maryland's bike master plan echoes this design guidance.
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Old 09-15-10, 05:48 AM   #11
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So death from those pesky bumps from behind make up 0.3% of all bike crashes.

Listening to Bike Lanes notes that many rear end collisions happen to cyclists who are riding at night with no lights. What percentage of fatal rear-end collisions happen in daylight I wonder, and how much does visibility (or rather lack of it) play a part in these collisions. Also, what percentage of night-time fatalities due to rear-enders happen to cyclists who are using lights and reflective clothing?

Listening to Bike Lanes also says:
Quote:
"in the lion’s share of Type 13 crashes, the bicyclists had failed to make themselves visible with lights at night."
But I can't find the actual figures for what constitutes this 'lion's share'.
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Old 09-15-10, 05:53 AM   #12
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Visibility alone will not allow cyclists to reclaim the streets with the vehicle improved roads were MADE for.

Visibility and a conspicuous road position is a woefully inadequate pipe dream about how to plan for bikes in the transportation grid.
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