Posted on 05/07/2008 12:16:43 PM PDT by jim_trent
RED LIGHT CAMERA SYSTEM DEVELOPMENT AND PLACEMENT FOR INTERSECTION SAFETY WEB SEMINAR
Date: Tuesday, May 20, 2008 Time: 2:00 p.m.-3:30 p.m. Eastern Credit: 1.5 PDH/.15 IACET CEU
Background: Red light running is a serious safety issue at many intersections in the US and other countries. Cameras that automatically record red light violators and provide the means for issuing citations by mail have been shown to reduce the collision toll under some circumstances over the past few years.
However, the success of a camera program depends upon many good decisions being made by the responsible jurisdiction and engineers. This course will instruct engineers on the basics for considering a red light running camera enforcement program to enhance intersection safety.
Students should realize that the scope of the course does not include the details of camera operation or program administration. These details are important but vary widely by vendor and jurisdiction.
Learning Objectives: At the conclusion of the course, participants should be able to:
1) Recite basic statistics on red light running
2) Discuss the major reasons that drivers run red lights and cause collisions
3) Recall general findings from the literature on camera effectiveness
4) Recite other countermeasures for red light running collisions besides cameras that may be effective in some places
5) Discuss the basic criteria that guide effective choices of intersection approaches to receive cameras
6) Argue the key aspects of effective camera systems such as grace periods, signing, public information, and driver versus vehicle citations
7) Discuss the need for camera system oversight and periodic effectiveness evaluation
Intended Audience: Traffic engineers, transportation engineers, consultants and TOPS, PTOE and TSOS certificants
Generally, this is the best solution. The exact duration may be able to be tweaked a bit, but there will be a large overall reduction in T-bones and revenue.
Red Light Camera Studies Roundup
A collection of red light camera studies over the last decade shows red light cameras have serious side-effects.
Over the past decade, a number of studies have examined the use of red light cameras. The most relevant studies examined the devices in light of changes in traffic and engineering conditions made at intersections during the study period and pulled actual police reports to examine the particular causes of each collision. The following studies are the most comprehensive available:
A 2008 University of South Florida report found:
"Comprehensive studies conclude cameras actually increase crashes and injuries, providing a safety argument not to install them.... public policy should avoid conflicts of interest that enhance revenues for government and private interests at the risk of public safety."
A 2007 Virginia Department of Transportation study found:
"The cameras were associated with an increase in total crashes... The aggregate EB results suggested that this increase was 29%... The cameras were associated with an increase in the frequency of injury crashes... The aggregate EB results suggested an 18% increase, although the point estimates for individual jurisdictions were substantially higher (59%, 79%, or 89% increases) or lower (6% increase or a 5% decrease)."
A 2006 Winnipeg, Canada city audit found:
"The graph shows an increase of 58% in the number of traffic collisions from 2003 to 2004.... Contrary to long-term expectations, the chart shows an increase in claims at each level of damage with the largest percentage increase appearing at the highest dollar value."
A 2005 Virginia DOT study found:
"The cameras are correlated with an increase in total crashes of 8% to 17%."
In 2005, The Washington Post found:
"The analysis shows that the number of crashes at locations with cameras more than doubled, from 365 collisions in 1998 to 755 last year. Injury and fatal crashes climbed 81 percent, from 144 such wrecks to 262. Broadside crashes, also known as right-angle or T-bone collisions, rose 30 percent, from 81 to 106 during that time frame."
A 2004 North Carolina A&T University study found:
"Our findings are more pessimistic, finding no change in angle accidents and large increases in rear-end crashes and many other types of crashes relative to other intersections."
A 2003 Ontario Ministry of Transportation study found: "Compared to the average number of reported collisions occurring in the before period, the average yearly number of reported collisions increased 15.1 per cent in the after period."
Related Reports and Studies
The importance of the yellow warning signal time in reducing the instances of red light running is found in the following reports:
A 2004 Texas Transportation Institute study found:
"An increase in yellow duration of 1.0 seconds is associated with a [crash frequency] of about 0.6, which corresponds to a 40 percent reduction in crashes."
A 2001 report by the Majority Leader of the U.S. House of Representatives found:
"The changes in the yellow signal timing regulations have resulted in the inadequate yellow times. And these inadequate yellow times are the likely cause of almost 80 percent of red light entries."
________________________________________
Note: The preceding excerpts have links to sources at the theNewspaper.com web page linked at the beginning of this post.
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.
The City I live in has about 900 intersections with traffic signals. The City does not have a traffic engineer to keep the computer in each one of them up to date. They hire private firms to do that.
They use type 170 controllers. In them there is room for up to 9 different timing plans. The minimum in almost all of them around here is 3 different plans (morning rush hour, evening rush hour, and all other times). Different plans mean different times for each color. Between each plan, there is also a transition built into the computer — and that also changes the color time. In addition, the timing for each light depends on the cars above the sensors in the pavement (or other types of monitors). There is a maximum and minimum time for each color in each direction, depending on the number of cars it senses.
It is entirely possible (theoretically) for EVERY SINGLE color in each direction to be a different stop-watch time during the day. There are about a dozen pages of printouts on the computer settings for each and every intersection that details how it is programmed. I assume that you took all of this into account when you stood nearby with your stopwatch.
Since the City does not have an engineer monitoring these around here, it is farmed out a private firms, including the one I work for. In a given working day, there are between a dozen and three-dozen changes made to timing. This is based on malfunctions, changes in traffic, new or widened streets nearby changing traffic patterns, new businesses that draw traffic, new housing developments, and new apartments. The traffic count is taken at about 300 intersections per year to get this information. Actually, the ITE recommends that traffic counts be taken yearly and the traffic light timing be reviewed and adjusted each year. It never gets done, but that is ideal, of course and that would cost 3 times the money.
In case you have not guessed by now, I will spell it out more plainly. Standing nearby with a stop-watch at one time and then comparing it with a different time will tell you absolutely nothing. You are spouting BS.
We don’t have Red-Light-cameras around here, yet. However, the only State Senator that was totally opposed to that was forced out by term limitations this year. I fully expect it to be authorized by the legislature next year.
There is no question that there are some studies that show more accidents and others that show fewer accidents. Like I said before, Traffic Engineering uses statistics more than any branch of engineering I have any experience with. For that reason alone, it is suspect. However, the trend is towards proof that Red-Light-cameras do make intersections slightly more safe on average.
The ITE formula that I have mentioned several times started out like that 70 years ago. There is more than enough proof that it works now. It has been studies to death. Anyone who says it doesn't is received like a “troother” or holocaust denier. Eventually, Red-Light-cameras will be the same.
My state is the permissive yellow, too.
One of the studies I included is frequently quoted around here by people who say that lengthening the yellow increases safety. However, they only quote what they want to hear from it. The guy who wrote it is pressing for the maximum ITE yellow time to go from 5.0 seconds to 5.5 seconds. From my understanding, the safety curve is essentially flat between 5.0 and 5.5 seconds. The establishment wants to leave it at 5.0 seconds. So he is arguing with the establishment over 1/2 of one second.
To read some of the people on this website, 7 to 10 seconds would be better. It would not. No peer reviewed article I know of supports that. Even the guy mentioned above agrees that anything more than 5.5 seconds is dangerous.
We include a one-second, all-red indication on all collector and primary roads. That is pretty well supported in the literature and in our experience as being better than longer yellows. That seems to help things around here, but the suggestions I hear about going to 3 seconds scare me. You only have 60 seconds in a minute to move traffic. Anything you do to reduce the number of vehicles that can pass through an intersection will make it more dangerous since people are impatient enough as it is.
But then that's not what I did. Sadly for you, I made the comparisons on the same day of week and the same time of day, excluded holidays and sporting events.
The minimum in almost all of them around here is 3 different plans (morning rush hour, evening rush hour, and all other times). Different plans mean different times for each color. Between each plan, there is also a transition built into the computer — and that also changes the color time. In addition, the timing for each light depends on the cars above the sensors in the pavement (or other types of monitors). There is a maximum and minimum time for each color in each direction, depending on the number of cars it senses.
I am aware of all of this, and it tends to make my argument.
There is a maximum and minimum time for each color
This is an admission that yellow light times are manipulated.
It is entirely possible (theoretically) for EVERY SINGLE color in each direction to be a different stop-watch time during the day.
A second admission that EVERY light is manipulated.
computer settings for each and every intersection that details how it is programmed. I assume that you took all of this into account when you stood nearby with your stopwatch.
Yes, it's not that hard.
In a given working day, there are between a dozen and three-dozen changes made to timing. This is based on malfunctions, changes in traffic, new or widened streets nearby changing traffic patterns, new businesses that draw traffic, new housing developments, and new apartments. it is farmed out to private firms, including the one I work for.
Again, manipulation, and you guys are great to be able to widen streets, build new ones, new businesses and apartments inside a DAY.
Actually, the ITE recommends that traffic counts be taken yearly and the traffic light timing be reviewed and adjusted each year. It never gets done
So there's nobody watching you?
We don’t have Red-Light-cameras around here, yet. I fully expect it to be authorized by the legislature next year.
And the contracting supplier getting a percentage, will that be yours?
You are spouting BS.
I can't hold a candle to you.
That pretty well nails it.
> “But then that’s not what I did. Sadly for you, I made the comparisons on the same day of week and the same time of day, excluded holidays and sporting events.”
And you had exactly the same number of cars on top of each sensor, too, I suppose. If not, the times WILL be different.
> “This is an admission that yellow light times are manipulated.”
You use the word manipulated as a weapon over and over. The times are “manipulated” within computer set boundaries to minimize the amount of red time whenever possible. I see that as helping the motorist — and so does the ITE.
> “Yes, it’s not that hard.”
Totally wrong, and you don’t even realize that. I would really, really like to see you set up the times on an intersection some day.
> “Again, manipulation, and you guys are great to be able to widen streets, build new ones, new businesses and apartments inside a DAY.”
Deliberately misrepresenting things again. The traffic timing is usually changed AFTER a traffic count, which is done after the traffic has stabilized after construction is done. The “manipulation” is done to reduce the amount of time spent on red based on the latest data.
> “So there’s nobody watching you?”
The politicians who hire us get reports on what we do every year. If they cannot handle it, maybe they should hire their OWN traffic engineer. They can do that you know. However, places that have done that usually end up with worse traffic timing because the POLITICIANS end up dictating what they want instead of what is best for the City as a whole.
> “And the contracting supplier getting a percentage, will that be yours?”
Wrong. We (and other engineering consulting firms that I am aware of) don’t do Red-Light-cameras. A completely different, self-contained “for profit” firm does that.
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I don’t doubt that the “profit” motive is driving Red-Light-cameras. That does not mean that they cannot increase safety, too.
The claim that times are deliberately manipulated to increase tickets (which means decrease safety) may be true, but it has not been proven to my satisfaction yet. I did take the time to track down the first case I saw posted here that claimed that and talked to the traffic engineer there. The claims in the article were completely wrong as most newspaper reporting is — especially on technical matters. For that reason, I question unsubstantiated claims from a website that has a very obvious axe to grind.
My city installed red light cameras without first checking their own county’s law that requires something like 70% of moving violation fines to be given to the school system.
They paid a contractor 70% to install, maintain and collect the fines. After a suit to challenge the legality of this was concluded the city had to pony up several million in taxpayer money to the school system and canned the cameras.
Try the site again. It worked for me. It’s the best series of articles explaining this.
Now my state is a bit different. IIRC for a city to place cameras it must show how those intersections are relatively more dangerous and thus deserving of a camera. In that case I have no problem with them.
Sounds like your City has stupid politicians. Do you honestly think that we engineers make the original decision to start placing Red-Light-cameras out?
“Sounds like your City has stupid politicians. Do you honestly think that we engineers make the original decision to start placing Red-Light-cameras out?”
My city has pathetically stupid politicians. How or why you implicated yourself is a mystery to me.
I guess you do think we make the decision. Sorry to burst your bubble, but the stupid politicians make that decision. After it is made, we do our best to make it work.
I have aften wondered if an engineer was actually caught manipulating the traffic light timing to decrease safety and an accident happened. I believe that , at the very least, he would lose his license.
The engineer who was involved in the walkway collapse in the Kansas City Hyatt Regency several years ago lost his license and was never allowed to practice engineering again. This in spite of the fact that he designed the connection correctly. The contractor found it hard to build, so he submitted an alternate plan — the one that failed. Somehow, it was never reviewed by the engineer, never approved, but it was built anyway. Because of that, he lost his livelyhood. I believe that engineers are stronger at policing their craft than any other professional. BTW, I think the Hyatt engineer became a politician — or was it a salesman.
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