If we had 85th percentile speed limits, longer yellow lights, sufficient length all-reds, and sensors to monitor traffic, no crashes! Can sync lights too.
The latest Insurance Institute for Highway Safety (IIHS) report appears to use the same statistical trickery as earlier pro-camera reports the organization has issued. For instance:
1.Their researchers award safety credit to red-light cameras based on the halo or spillover effect. Essentially if a city has red-light cameras at some intersections, IIHS credits the cameras for favorable safety numbers at all intersections throughout the city, cameras or no cameras. Car and Driver’sPatrick Bedard aptly commented about this tactic in 2002 (that’s how long IIHS has been using it in their reports): “Spillover effect is IIHS’s trick for giving the cameras credit for reducing fatalities even where they aren’t. It assumes that red-light cameras at a few intersections will cause drivers to stop promptly all over town, or all over the county, or maybe all over the state, so improvements outside the cameras’ ZIP Codes are credited to them nonetheless. As statistical acrobatics go, this one is breathtaking.”
2.IIHS is reporting “fatal crashes at signalized intersections.” That number usually quite small within any given city. The difference between a couple of accidents in year one and a couple more in year two can make a statistical anomaly look like a 50 to 100 percent increase.
3.IIHS doesn’t release their data. The information that forms the basis of these types of reports can’t be peer reviewed let alone replicated. Therefore the IIHS report is not a scientific study.
The IIHS press release for this report states, “Although surveys have found strong support for red light cameras in communities that have them, opposition from a vocal minority has led some jurisdictions to shut off their cameras.” Contrast that with the facts. Since 1991, 38 communities throughout the United States have put their red-light and/or speed cameras on the public ballot for an up-or-down vote. Thirty-four of them – 90 percent – voted to shut down the camera programs, in many instances by overwhelming majorities. The term “vocal minority” used by the IIHS displays a pro-camera bias to their thinking.
The IIHS is a non-profit organization funded by auto insurers. Since the IIHS first-and-foremost represents the interests of the 80 insurance companies from which it receives its funding, it has been suggested that a primary motivation is to influence public opinion and legislation aimed at making insurance companies more profitable.
—————-
First:
Before the Philadelphia red light cameras were installed they lengthened the yellow intervals by one second on ONLY four or six lights – not on all the projected camera sites. (I don’t have access to my records on whether it was four or six.) It is likely these few lights had yellow intervals that were well over one second too short and needed even more adjustment to be correctly timed for safety. Using this too-limited sample allowed them to make the false claim that the cameras had a lot more to do with reducing the violations than adjusting the yellow intervals.
Other cities have adjusted yellow intervals by 0.7 to a little more than 1.0 seconds and achieved violation reductions of 70% to 90%. Note that the reductions are permanent, not temporary as some of the for-profit camera companies claim. Violation rates do NOT rebound and drivers do NOT “take advantage” of the longer yellows to “push the point”. We have collected the data from many sources to prove this point, and you can access those studies at this URL.
Note that neither federal nor most state DOT rules require setting yellow intervals long enough for safety. The federal rule in the Manual of Uniform Traffic Control Devices that all states must use of 3.0 to 6.0 seconds is utterly useless because it does not require a sliding scale based on approach speeds. The NMA and some officials in the Federal Highway Administration tried to get this rule strengthened, but failed to do so a couple of years ago.
The formula for the yellow intervals (on level ground) has two components. One is the perception/reaction time and it is usually used as 1.0 seconds, but that accommodates only about half the drivers. The proper time is 1.4 seconds which accommodates about 85% of the drivers. Florida mandated that change in 2013 and got a 30% to 50% reduction in straight through violations at most camera sites. The other component is the approach speed which the original formula writers meant to be the ACTUAL 85th percentile speeds of free flowing traffic under good conditions (speed at or below which you find 85% of the drivers). This has been improperly changed to the posted limit by most camera cities. However, far too many posted speed limits are set about 10 mph below the safest 85th percentile speed points, so that makes the yellows too short by about 0.7 seconds. Add the 0.4 short for the perception/reaction time and the 0.7 for the approach speed and you have yellows short by about 1.1 seconds. NOW note the research and the examples in the URL above which shows about 80% of the violations are in the first second of red – and you have a clear view on why the for-profit red light camera industry can make such high profits to share with their city business partners wherever the yellow intervals are improperly set.
Note also that data obtained by independent investigative reporters from the Philadelphia Police Department (which does not share in the camera revenue) showed the total crash rates in Philadelphia were higher at camera intersections, both in 2005 when the program was new and continuing in 2011 when it was renewed.
Second:
The IIHS is a highly biased source of information for anything that relates to red light cameras, speed cameras, and speed limits because in some states the member insurance companies can add surcharges to raise the insurance premiums of drivers who get tickets from cameras or officers. So, set the yellow intervals on the lights about one second too short to produce perhaps five times the number of tickets that would happen with correct timing, and the profit potential of those surcharges gets pretty obvious. Similarly, set speed limits about 10 mph lower than the safest points, and the surcharges to drivers caught in those speed traps become almost pure profit.
Note that the IIHS presented a major “study” about red light cameras improving safety at camera intersections. The University of South Florida analyzed the same set of data, but corrected several flaws in the research methodology and showed that the cameras actually decreased safety.
The IIHS has done wonderful work with more rigid crash tests than required by NHTSA, and auto makers have improved the crashworthiness of their vehicles by large margins in order to get good “scores” on the IIHS crash tests. But their “research” and “studies” about speed limits, speed cameras and red light cameras are so biased by their financial involvement in the ticket revenue stream that you should look for other sources in our view. We think the best traffic safety research comes from unbiased academic sources and investigative reporters – people and groups that have no share in the ticket revenue stream or the resulting insurance surcharges.
Another biased study. Read this link from FL:
http://www.wtsp.com/news/investigations/study-suggests-red-light-camers-save-livesbut/283440987
If we had 85th percentile speed limits, longer yellow lights, sufficient length all-reds, and sensors to monitor traffic, no crashes! Can sync lights too.
The latest Insurance Institute for Highway Safety (IIHS) report appears to use the same statistical trickery as earlier pro-camera reports the organization has issued. For instance:
1.Their researchers award safety credit to red-light cameras based on the halo or spillover effect. Essentially if a city has red-light cameras at some intersections, IIHS credits the cameras for favorable safety numbers at all intersections throughout the city, cameras or no cameras. Car and Driver’sPatrick Bedard aptly commented about this tactic in 2002 (that’s how long IIHS has been using it in their reports): “Spillover effect is IIHS’s trick for giving the cameras credit for reducing fatalities even where they aren’t. It assumes that red-light cameras at a few intersections will cause drivers to stop promptly all over town, or all over the county, or maybe all over the state, so improvements outside the cameras’ ZIP Codes are credited to them nonetheless. As statistical acrobatics go, this one is breathtaking.”
2.IIHS is reporting “fatal crashes at signalized intersections.” That number usually quite small within any given city. The difference between a couple of accidents in year one and a couple more in year two can make a statistical anomaly look like a 50 to 100 percent increase.
3.IIHS doesn’t release their data. The information that forms the basis of these types of reports can’t be peer reviewed let alone replicated. Therefore the IIHS report is not a scientific study.
The IIHS press release for this report states, “Although surveys have found strong support for red light cameras in communities that have them, opposition from a vocal minority has led some jurisdictions to shut off their cameras.” Contrast that with the facts. Since 1991, 38 communities throughout the United States have put their red-light and/or speed cameras on the public ballot for an up-or-down vote. Thirty-four of them – 90 percent – voted to shut down the camera programs, in many instances by overwhelming majorities. The term “vocal minority” used by the IIHS displays a pro-camera bias to their thinking.
The IIHS is a non-profit organization funded by auto insurers. Since the IIHS first-and-foremost represents the interests of the 80 insurance companies from which it receives its funding, it has been suggested that a primary motivation is to influence public opinion and legislation aimed at making insurance companies more profitable.
—————-
First:
Before the Philadelphia red light cameras were installed they lengthened the yellow intervals by one second on ONLY four or six lights – not on all the projected camera sites. (I don’t have access to my records on whether it was four or six.) It is likely these few lights had yellow intervals that were well over one second too short and needed even more adjustment to be correctly timed for safety. Using this too-limited sample allowed them to make the false claim that the cameras had a lot more to do with reducing the violations than adjusting the yellow intervals.
Other cities have adjusted yellow intervals by 0.7 to a little more than 1.0 seconds and achieved violation reductions of 70% to 90%. Note that the reductions are permanent, not temporary as some of the for-profit camera companies claim. Violation rates do NOT rebound and drivers do NOT “take advantage” of the longer yellows to “push the point”. We have collected the data from many sources to prove this point, and you can access those studies at this URL.
https://www.motorists.org/issues/red-light-cameras/yellow-lights
Note that neither federal nor most state DOT rules require setting yellow intervals long enough for safety. The federal rule in the Manual of Uniform Traffic Control Devices that all states must use of 3.0 to 6.0 seconds is utterly useless because it does not require a sliding scale based on approach speeds. The NMA and some officials in the Federal Highway Administration tried to get this rule strengthened, but failed to do so a couple of years ago.
The formula for the yellow intervals (on level ground) has two components. One is the perception/reaction time and it is usually used as 1.0 seconds, but that accommodates only about half the drivers. The proper time is 1.4 seconds which accommodates about 85% of the drivers. Florida mandated that change in 2013 and got a 30% to 50% reduction in straight through violations at most camera sites. The other component is the approach speed which the original formula writers meant to be the ACTUAL 85th percentile speeds of free flowing traffic under good conditions (speed at or below which you find 85% of the drivers). This has been improperly changed to the posted limit by most camera cities. However, far too many posted speed limits are set about 10 mph below the safest 85th percentile speed points, so that makes the yellows too short by about 0.7 seconds. Add the 0.4 short for the perception/reaction time and the 0.7 for the approach speed and you have yellows short by about 1.1 seconds. NOW note the research and the examples in the URL above which shows about 80% of the violations are in the first second of red – and you have a clear view on why the for-profit red light camera industry can make such high profits to share with their city business partners wherever the yellow intervals are improperly set.
Note also that data obtained by independent investigative reporters from the Philadelphia Police Department (which does not share in the camera revenue) showed the total crash rates in Philadelphia were higher at camera intersections, both in 2005 when the program was new and continuing in 2011 when it was renewed.
Second:
The IIHS is a highly biased source of information for anything that relates to red light cameras, speed cameras, and speed limits because in some states the member insurance companies can add surcharges to raise the insurance premiums of drivers who get tickets from cameras or officers. So, set the yellow intervals on the lights about one second too short to produce perhaps five times the number of tickets that would happen with correct timing, and the profit potential of those surcharges gets pretty obvious. Similarly, set speed limits about 10 mph lower than the safest points, and the surcharges to drivers caught in those speed traps become almost pure profit.
Note that the IIHS presented a major “study” about red light cameras improving safety at camera intersections. The University of South Florida analyzed the same set of data, but corrected several flaws in the research methodology and showed that the cameras actually decreased safety.
The IIHS has done wonderful work with more rigid crash tests than required by NHTSA, and auto makers have improved the crashworthiness of their vehicles by large margins in order to get good “scores” on the IIHS crash tests. But their “research” and “studies” about speed limits, speed cameras and red light cameras are so biased by their financial involvement in the ticket revenue stream that you should look for other sources in our view. We think the best traffic safety research comes from unbiased academic sources and investigative reporters – people and groups that have no share in the ticket revenue stream or the resulting insurance surcharges.