Comments on: Cross and Fisher 1977 http://azbikelaw.org/blog/cross-and-fisher-1977/ Cycling, traffic safety and legal topics; energy, transit and transportion economics Wed, 08 Feb 2012 15:34:11 +0000 hourly 1 http://wordpress.org/?v=3.3 By: azbikelaw http://azbikelaw.org/blog/cross-and-fisher-1977/comment-page-1/#comment-10209 azbikelaw Sat, 24 Sep 2011 20:38:08 +0000 http://azbikelaw.org/blog/cross-and-fisher-1977/#comment-10209 I recently became the proud owner of a copy of Forester's classic <em><a href="http://books.google.com/books/about/Bicycle_transportation.html?id=Qz4kAulpimgC" rel="nofollow">Bicycle Transportation</a></em>, 2nd edition, 1994. In it he discusses the Cross and Fisher data at great length and detail. In table 5-8 and 5-10; he re-splits the crash types into sub-types which illuminate fault basis to a great extent. The splits are c/s/w/t for: correct road position, sidewalk, wrong side of road, and cyclist swerve (why is that one t? t=turn?) He states, without any furthere explanation as to how these seeminly precise (down to the ten-thousandths!): "The statistical error in sample stratification is that ruarl and urban car-bike collisions were sampled by diffreent plans but are grouped as if they had been sampled by one plan. As a result rural collisions are overstated by a factor of 1.454 while urban collisions are understated by a factor of 0.9663" I can't quite see how the numbers to jive up, so to take an example of crash type 5 which according to the <a href="http://www.truewheelers.org/research/studies/aaa/05types.htm#classb" rel="nofollow">web-version</a> of Cross and Fisher equals 10.2% of the 761 non-fatals, with the text elaboration saying that only 4% of this type were at rural intersections. So, in table 5-8 & 10 of Bicycle Transportation, Type 5 appears broken into three incarnations: 5c/urban = 9.3%, 5w/urban = 2.6%, and 5c/rural = 2.0% I recently became the proud owner of a copy of Forester’s classic Bicycle Transportation, 2nd edition, 1994. In it he discusses the Cross and Fisher data at great length and detail.
In table 5-8 and 5-10; he re-splits the crash types into sub-types which illuminate fault basis to a great extent. The splits are c/s/w/t for: correct road position, sidewalk, wrong side of road, and cyclist swerve (why is that one t? t=turn?)
He states, without any furthere explanation as to how these seeminly precise (down to the ten-thousandths!):
“The statistical error in sample stratification is that ruarl and urban car-bike collisions were sampled by diffreent plans but are grouped as if they had been sampled by one plan. As a result rural collisions are overstated by a factor of 1.454 while urban collisions are understated by a factor of 0.9663″

I can’t quite see how the numbers to jive up, so to take an example of crash type 5 which according to the web-version of Cross and Fisher equals 10.2% of the 761 non-fatals, with the text elaboration saying that only 4% of this type were at rural intersections.
So, in table 5-8 & 10 of Bicycle Transportation, Type 5 appears broken into three incarnations: 5c/urban = 9.3%, 5w/urban = 2.6%, and 5c/rural = 2.0%

]]> By: 2009 Arizona Bicyclist Fatality Report @ Arizona Bike Law Blog http://azbikelaw.org/blog/cross-and-fisher-1977/comment-page-1/#comment-4748 2009 Arizona Bicyclist Fatality Report @ Arizona Bike Law Blog Fri, 08 Oct 2010 22:11:35 +0000 http://azbikelaw.org/blog/cross-and-fisher-1977/#comment-4748 [...] Carol Tan paper crash-type [...] [...] Carol Tan paper crash-type [...]

]]> By: Pre-preliminary 2009 Fatality Report @ Arizona Bike Law Blog http://azbikelaw.org/blog/cross-and-fisher-1977/comment-page-1/#comment-2204 Pre-preliminary 2009 Fatality Report @ Arizona Bike Law Blog Wed, 18 Nov 2009 22:55:17 +0000 http://azbikelaw.org/blog/cross-and-fisher-1977/#comment-2204 [...] summary described on cyclicious (and on treehugger), these diagrams look familiar(? maybe the Carol Tan paper?) safety cyclist fatality, [...] [...] summary described on cyclicious (and on treehugger), these diagrams look familiar(? maybe the Carol Tan paper?) safety cyclist fatality, [...]

]]> By: Arizona Bike Law Blog » Blog Archive » Ahwatukee cyclist is killed in collision with parked truck http://azbikelaw.org/blog/cross-and-fisher-1977/comment-page-1/#comment-791 Arizona Bike Law Blog » Blog Archive » Ahwatukee cyclist is killed in collision with parked truck Tue, 03 Feb 2009 05:41:23 +0000 http://azbikelaw.org/blog/cross-and-fisher-1977/#comment-791 [...] Cross and Fisher for more discussion of that and the Tan [...] [...] Cross and Fisher for more discussion of that and the Tan [...]

]]> By: Arizona Bike Law Blog » Blog Archive » Understanding Collision Summaries http://azbikelaw.org/blog/cross-and-fisher-1977/comment-page-1/#comment-103 Arizona Bike Law Blog » Blog Archive » Understanding Collision Summaries Sun, 21 Oct 2007 23:52:26 +0000 http://azbikelaw.org/blog/cross-and-fisher-1977/#comment-103 [...] Arizona Bike Law Blog « Cross and Fisher 1977 [...] [...] Arizona Bike Law Blog « Cross and Fisher 1977 [...]

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