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Sidewalks, bikes, & civil engineering
James wrote:
Dan O wrote: On Sep 22, 10:21 pm, James wrote: damyth wrote: NPR had some coverage today regarding federal funding of bike infrastructure. http://www.npr.org/2011/09/22/140709...ture-hits-cong... The report itself wasn't all that interesting, but in the comments section, a purported civil engineer (JaredParker) "specializing in traffic engineering and transportation" said this in response to another comment: "@Greg Smith (jatodog) 'Sidewalks are the most dangerous place for bikes, for both cyclists and pedestrians. If you ever rode a bike more than a few hours a year, you'd know that.' Actually Greg, I'd like to see your data regarding cyclist and pedestrian "dangers". I am Civil Engineer specializing in traffic engineering and transportation planning. The data that the NHTSA has released and data in studies that my company has conducted show that sidewalks are, on average, actually much safer for cyclists, at a rate of 60-75% less injuries and fatalities sustained by cyclists who use the sidewalk vs. the road. To more appropriately address the issue of cyclists and transportation, sidewalks could be converted into bike lanes much more readily than attempting to dedicate lanes of road to the cause, considering the easement and space is already there. Asphalt overlays and striping to separate pedestrian and bike traffic on the sidewalk is a very cost effective and safe alternative to exposing bikers to traffic in most urban and suburban settings. And by the way, I am an avid biker; and, I bike a minimum of 20 miles per day, weather cooperating. And I use the sidewalk." What the hell? Every driveway is a blind intersection. With civil engineers "specializing in traffic engineering and transportation planning" like this, who needs enemies? Yup, I agree. I guess if you ride very slowly, like at walking speed, the footpath might be ok, but for most people who ride regularly, the footpath is not an option. I'd like to see how long this civil eng. would survive at 40 km/h on the footpath. Riding on the sidewalk introduces some profound hazards of its own, but offers unique protections and conveniences as well. As long as the rider is cognizant of the implications, sidewalks are a great option to *include* in panoply of choices. I know there are times when it becomes useful, the question is, would you ride exclusively on the footpath, for a minimum of 20 miles per day? I might ride a short distance on the footpath, to avoid for example a traffic jam, road works, or open street festival like: http://www.hispanicfiesta.com.au/ But once the road is clear of obstruction, it's the safest place to be at any sort of reasonable riding speed. Here's a blog that analyzes Phoenix Arizona's latest bike crash report. http://azbikelaw.org/blog/listening-...ision-summary/ The author's major points: Sidewalks seem MUCH more dangerous than roads, and cycling by vehicle rules seems MUCH safer than being, um, creative. That's shown by the table, indicating whether the cyclist's action pre-crash would be deemed "good" or "bad" by VC standards. Only 10% of crashes involved "good" VC behavior. A full 70% happened to sidewalk cyclists. Unfortunately, there's no exposure data, which means it's possible that only 10% of the cycling in Phoenix is done according to the rules of the road, and that 70% of Phoenix's cycling is done on sidewalks. But I think that's highly unlikely. I also think it's likely that most of the rule-flouting cyclists figured they were being really smart - i.e. much smarter than those cyclists following normal traffic rules. -- - Frank Krygowski |
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#2
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Sidewalks, bikes, & civil engineering
Per Frank Krygowski:
The author's major points: Sidewalks seem MUCH more dangerous than roads, and cycling by vehicle rules seems MUCH safer than being, um, creative. I only skimmed the web page, but this jumped out at me: "...and nothing is split by seriousness..." Is he saying that the data only records "Collision" vs "Non-Collision"? i.e. The data does (do?) not discriminate between something like road rash/bruises and getting squashed by a bus? -- PeteCresswell |
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Sidewalks, bikes, & civil engineering
(PeteCresswell) wrote:
Per Frank Krygowski: The author's major points: Sidewalks seem MUCH more dangerous than roads, and cycling by vehicle rules seems MUCH safer than being, um, creative. I only skimmed the web page, but this jumped out at me: "...and nothing is split by seriousness..." Is he saying that the data only records "Collision" vs "Non-Collision"? i.e. The data does (do?) not discriminate between something like road rash/bruises and getting squashed by a bus? The original report at http://phoenix.gov/STREETS/2007bike.pdf does count the number of "serious or fatal" crashes, 63 of them. It doesn't break down crash types by serious vs. minor, from what I can see. -- - Frank Krygowski |
#4
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Sidewalks, bikes, & civil engineering
The original report at
http://phoenix.gov/STREETS/2007bike.pdf =v= As usual, based on police reports and thus subject to the observer bias of police and, in the case of fatalities, survivor bias. So the "at-fault" numbers and charts are completely meaningless, but will of course be used to prop up the usual entrenched opinions anyhow. The other stats are of more value, of course, though they depend on how much forensic work the police decide to do when a bike is involved. _Jym_ |
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Sidewalks, bikes, & civil engineering
Jym Dyer wrote:
The original report at http://phoenix.gov/STREETS/2007bike.pdf =v= As usual, based on police reports and thus subject to the observer bias of police and, in the case of fatalities, survivor bias. So the "at-fault" numbers and charts are completely meaningless, but will of course be used to prop up the usual entrenched opinions anyhow. The other stats are of more value, of course, though they depend on how much forensic work the police decide to do when a bike is involved. _Jym_ When someone says "That data is useless," it's good form to give other data that's better. So: Got data on Phoenix? Or got other data that proves what you claim? -- - Frank Krygowski |
#6
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Sidewalks, bikes, & civil engineering
On Sep 26, 9:30 am, Frank Krygowski
wrote: I also think it's likely that most of the rule-flouting cyclists figured they were being really smart - i.e. much smarter than those cyclists following normal traffic rules. I know that's your fantasy. Reality is that a high percentage of those 'rule-flouting cyclists' were actually little kids riding their bikes like little kids, on and off the sidewalks. Studying the crashes suffered by little kids on bikes is of course of very limited utility for adult cyclists. |
#7
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Sidewalks, bikes, & civil engineering
Jym Dyer wrote:
The original report at http://phoenix.gov/STREETS/2007bike.pdf =v= As usual, based on police reports and thus subject to the observer bias of police and, in the case of fatalities, survivor bias. So the "at-fault" numbers and charts are completely meaningless, but will of course be used to prop up the usual entrenched opinions anyhow. The other stats are of more value, of course, though they depend on how much forensic work the police decide to do when a bike is involved. _Jym_ When someone says "That data is useless," it's good form to give other data that's better. So: Got data on Phoenix? Or got other data that proves what you claim? -- - Frank Krygowski |
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Sidewalks, bikes, & civil engineering
When someone says "That data is useless," it's good form
to give other data that's better. =v= That would be great if other data were available. If it's not, that doesn't mean the bad data is suddenly good. _Jym_ |
#9
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Sidewalks, bikes, & civil engineering
Jym Dyer wrote:
When someone says "That data is useless," it's good form to give other data that's better. =v= That would be great if other data were available. If it's not, that doesn't mean the bad data is suddenly good. _Jym_ So what you're saying is "_All_ the data is bad. I just know it is. You just have to believe me." Sorry. I think unquestioning faith in a self-proclaimed prophet is kind of dangerous. -- - Frank Krygowski |
#10
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Sidewalks, bikes, & civil engineering
Frank Krygowski writes:
So what you're saying is "_All_ the data is bad. I just know it is. You just have to believe me." =v= What I actually said is that *part* of the data is subject to bias: namely, the at-fault numbers. Sorry. I think unquestioning faith in a self-proclaimed prophet is kind of dangerous. =v= Now you're really off the rails. I named specific and well-known forms of bias (observer bias and survivor bias). I did not invent these insights, I'm just applying them. If you have any substantial, non-_ad_hominem_ reason why these biases should simply be ignored, by all means present them. _Jym_ |
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