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  #1  
Old September 23rd 14, 05:57 AM posted to rec.bicycles.tech
Ralph Barone[_3_]
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Posts: 321
Default Cheap bright tail light

Frank Krygowski wrote:
On 9/22/2014 3:39 PM, Joerg wrote:
Frank Krygowski wrote:

[...]

Seriously - you brought up the paper at
http://www.vehicularcyclist.com/copenhagen2.pdf

Let's discuss it!


Crashes - all - observed before 389 --- observed after 311. Fatalities
went from 3 to zero. So, there. How can it be more clear?


Perhaps it can be made more clear if you actually read the paper?

As they attempted to explain, the "Observed before" included situations
where several things about the road had changed. One major point of the
paper was their method for separating out the effects of non-cycletrack
changes, to more accurately gauge the change due to the cycletrack alone.
As they explain, the proper comparison is the one between "Expected
AFTER" and "Observed AFTER."

That change is: 295 vs. 311. In other words, they'd expect 295 total
crashes among all user types if there were no cycletracks, but they found
311 instead. The increase was due to the cycletracks.

It's true, that's not a terrible increase, only 5%. But that's because
you're talking mostly about non-injury crashes (very mild ones) and
you're including mostly crashes between two motor vehicles. Much more
interesting to us should be bicyclist injuries, no? That's who
cycletracks are _claimed_ to help, after all. Yet bicyclist (and moped)
injuries are absolutely higher, no matter which data columns you compare.

It seems your argument is to ignore the bad injury data for cyclists, the
people you're claiming cycletracks must benefit, and look only at the one
bit of data dominated by motorists, very few of whom were injured anyway.

It's a strange argument.



The one thing I found confusing about the paper was their use of "Safety
Effect" as a table heading instead of "Hazard Effect", since positive
numbers in that column appear to indicate lower safety.
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  #2  
Old September 23rd 14, 05:32 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default Cheap bright tail light

On 9/23/2014 12:57 AM, Ralph Barone wrote:
Frank Krygowski wrote:
On 9/22/2014 3:39 PM, Joerg wrote:
Frank Krygowski wrote:

[...]

Seriously - you brought up the paper at
http://www.vehicularcyclist.com/copenhagen2.pdf

Let's discuss it!


Crashes - all - observed before 389 --- observed after 311. Fatalities
went from 3 to zero. So, there. How can it be more clear?


Perhaps it can be made more clear if you actually read the paper?

As they attempted to explain, the "Observed before" included situations
where several things about the road had changed. One major point of the
paper was their method for separating out the effects of non-cycletrack
changes, to more accurately gauge the change due to the cycletrack alone.
As they explain, the proper comparison is the one between "Expected
AFTER" and "Observed AFTER."

That change is: 295 vs. 311. In other words, they'd expect 295 total
crashes among all user types if there were no cycletracks, but they found
311 instead. The increase was due to the cycletracks.

It's true, that's not a terrible increase, only 5%. But that's because
you're talking mostly about non-injury crashes (very mild ones) and
you're including mostly crashes between two motor vehicles. Much more
interesting to us should be bicyclist injuries, no? That's who
cycletracks are _claimed_ to help, after all. Yet bicyclist (and moped)
injuries are absolutely higher, no matter which data columns you compare.

It seems your argument is to ignore the bad injury data for cyclists, the
people you're claiming cycletracks must benefit, and look only at the one
bit of data dominated by motorists, very few of whom were injured anyway.

It's a strange argument.



The one thing I found confusing about the paper was their use of "Safety
Effect" as a table heading instead of "Hazard Effect", since positive
numbers in that column appear to indicate lower safety.


I agree. Yes, the increases shown are actually hazard increases. The
crash counts and injury counts make that clear.

When I first read that paper, I had to stop, get a pencil, and begin
taking notes in the margins. I assume the difficulty is due to the fact
that the authors' first language is Danish, not English.

--
- Frank Krygowski
  #3  
Old September 24th 14, 06:07 AM posted to rec.bicycles.tech
Ralph Barone[_3_]
external usenet poster
 
Posts: 321
Default Cheap bright tail light

Frank Krygowski wrote:
On 9/23/2014 12:57 AM, Ralph Barone wrote:
Frank Krygowski wrote:
On 9/22/2014 3:39 PM, Joerg wrote:
Frank Krygowski wrote:

[...]

Seriously - you brought up the paper at
http://www.vehicularcyclist.com/copenhagen2.pdf

Let's discuss it!


Crashes - all - observed before 389 --- observed after 311. Fatalities
went from 3 to zero. So, there. How can it be more clear?

Perhaps it can be made more clear if you actually read the paper?

As they attempted to explain, the "Observed before" included situations
where several things about the road had changed. One major point of the
paper was their method for separating out the effects of non-cycletrack
changes, to more accurately gauge the change due to the cycletrack alone.
As they explain, the proper comparison is the one between "Expected
AFTER" and "Observed AFTER."

That change is: 295 vs. 311. In other words, they'd expect 295 total
crashes among all user types if there were no cycletracks, but they found
311 instead. The increase was due to the cycletracks.

It's true, that's not a terrible increase, only 5%. But that's because
you're talking mostly about non-injury crashes (very mild ones) and
you're including mostly crashes between two motor vehicles. Much more
interesting to us should be bicyclist injuries, no? That's who
cycletracks are _claimed_ to help, after all. Yet bicyclist (and moped)
injuries are absolutely higher, no matter which data columns you compare.

It seems your argument is to ignore the bad injury data for cyclists, the
people you're claiming cycletracks must benefit, and look only at the one
bit of data dominated by motorists, very few of whom were injured anyway.

It's a strange argument.



The one thing I found confusing about the paper was their use of "Safety
Effect" as a table heading instead of "Hazard Effect", since positive
numbers in that column appear to indicate lower safety.


I agree. Yes, the increases shown are actually hazard increases. The
crash counts and injury counts make that clear.

When I first read that paper, I had to stop, get a pencil, and begin
taking notes in the margins. I assume the difficulty is due to the fact
that the authors' first language is Danish, not English.



I certainly would have done a worse job of writing a paper in Danish.
There's nothing like having at least one author on a paper who grew up
speaking the language the paper is to be written in. I was considering
starting a technical proof reading service for IEEE papers with a retired
co-worker, but he unfortunately died before we got anywhere with that.
 




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