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To: NonValueAdded

Here are several posted studies (back when I was looking at them).

http://www.motorists.com/issues/enforce/studies/TRB2004-001228.pdf
http://tti.tamu.edu/documents/4027-2.pdf
http://www.ltrc.lsu.edu/TRB_82/TRB2003-000136.pdf
http://www.ltrc.lsu.edu/TRB_82/TRB2003-000943.pdf
http://www.ltrc.lsu.edu/TRB_82/TRB2003-000285.pdf
http://stc.utk.edu/htm/pdf%20files/red.pdf
http://www.uritc.uri.edu/media/finalreportspdf/536146.pdf

However, I do not believe they back up what you say. The way the literature says they are supposed to be set up is to have the camera come on the moment the signal turns red. Anyone entering the intersection after that gets a ticket. Anyone entering the intersection before that should not get a ticket.

Lengthing the yellow indication to longer than the ITE formula (generally 3 to 5 seconds, depending on several physical factors) does NOT increase safety. In most cases, it decreases safety. Unless the yellow indication time is set wrong to begin with, lengthing it will not increase safety.

The science of traffic control uses statistics more than any other form of engineering (and I have worked in several of them). Statistics can be twisted and misused, but it is starting to prove out that in most cases, Red-Light-Cameras do slightly increase safety. It greatly reduces T-bone accidents which are the kind that are most often fatal. However, it increases rear-end accidents. These kind of accidents usually have fewer deaths, fewer and less serious injuries, and less property damage.

I wish it did not have to be done because the reason it is being used is for revenue, not safety. In addition, it will make it easier to use more cameras resulting in further loss of privacy. But, it is coming. The groundwork for this was laid 10 years ago. It is just coming to fruition now.

I have been saying here that “congestion-pricing” in the next big thing on the horizon. It is now where Red-Light-cameras was 10 years ago. Now is the time to kill congestion-pricing. it is too late to kill Red-Light-cameras, but most here do not agree. In 10 years when they have to start paying money for absolutely NOTHING (which is what congestion-pricing is) you will hear their yells.


16 posted on 05/07/2008 1:23:28 PM PDT by jim_trent
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To: jim_trent
Thanks for the studies. I learn from the second one that you are familiar with the "permissive yellow" red light running occurs when you enter the intersection on red as opposed to the non-permissive variety where you must exit the intersection before red. I'm told the latter applies here in Florida; the study says Texas is permissive yellow and that roughly half the states are permissive.

The study did not list confusion as to the definition of running a read light (i.e. assuming permissive yellow in a non-permissive state) as a contributing factor. I suppose for a Texas study that's understandable while it would be significant for a non-permissive case study. (pp 2.2-2.3)

While that tamu study did say too long a yellow cycle will cause a small incidence of increased red-light running (RLR) p. 2.9, it also showed a substantial improvement in compliance with a one second increase (53% fewer RLR) p.5-20. The fifth summary finding on page 6-8 says a nominal increase of .5s to 1.5s of yellow still yields a 50% decrease in RLR's even considering the learned misbehavior. The College Sta. observations on page 5-29 bear that out.

23 posted on 05/07/2008 5:51:58 PM PDT by NonValueAdded (Who Would Montgomery Brewster Choose?)
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