New Mexico: Study Finds No Clear Red Light Camera Benefit
Thu, 08/30/2012 - 11:16am
 16 years
|
New Mexico State University (NMSU) researchers have updated their analysis of the effectiveness of red light cameras in Las Cruces. Despite their best efforts, the results of the interim study presented to the city council Monday failed to find any clear and convincing evidence that the red light camera program that began in March 2009 has had a beneficial impact on safety.
"The influence of the 'dilemma zone' is probably one of the major reasons for such a high percentage of the red light violations," the report explained. "A combination of shorter signal timing cycle and high traffic volume might have created many dilemma zones that caused indecisive drivers to violate the red light."
The report reads differently in context
When you read the section of the report which "The Newspaper" extracted its quote about the dilemma zone, it does read a little differently.
The influence of the “dilemma zone” is probably one of the major reasons for such a high
percentage of the RLV. It is also observed, however, that 28% of the RLV occurred more than 3
seconds after the red light signal. A combination of shorter signal timing cycle and high traffic
volume might have created many dilemma zones that caused indecisive drivers to violate the red
light. Some drivers might be intentionally violating the traffic law, however, there could be other
drivers, especially seniors, who might not react to the light change quick enough to stop their
vehicles. Note that we separated the red light violators into four groups according to the elapsed
time since the red light signal: (1) up to 1 second; (2) 1.1 to 2 seconds; (3) 2.1 to 3 seconds; and
(4) more than 3 seconds.
The graphic accompanying this section of the report shows 56% of the violations occurred within 1 second, 12% occurring 1 to 2 seconds after the light changed, 4% occurring between 2 and 3 seconds after the light changed and 28% occurring more than 3 seconds after the light changed. Just looking at these numbers you could surmise that for every 2 caught in "the dilemma zone", someone ran the light more than 3 seconds after it had turned red.
Now, I haven't read or digested the entire report but I think you will find additional quotes cited by the newspaper are also taken out of context.
Illiterate? Write for free help.
What?
Boxcar, you aren't accusing the news media of cherry-picking their quotes are you? It also sounds like you think they would slant their reporting to support the side of the question they favor. They wouldn't do anything like that....heaven forbid!!
heaven forbid!
The news media is always "fair and balanced."
Illiterate? Write for free help.
The Abstract
says
The findings that can be drawn from the trend and statistical analyses are in the following. The effect of the STOP is beneficial on the traffic safety at the Lohman & Telshor intersection since there were significant reductions on the total crash rates, mainly due to the reduction on the rear-end crash rates and the property-damage only crash rates. However, the Lohman & Walnut intersection experienced an overall, negative impact. After the STOP operation, there were significant increases in every category of the crashes. The Main & Solano intersection also experienced an overall, negative impact as a result of the STOP operation. After the camera was installed, the trend has an upward spike after which the rates remain steady until the deactivation, when they trend downward quickly indicating a negative effect made by installing the camera. The Valley & Avenida de Mesilla intersection showed a mixture of reduction and increment in the crash rates after the launch and deactivation of the STOP program. However, we cannot make a solid conclusion on the camera effect at the Valley & Avenida de Mesilla intersection since its southbound camera had deactivated and thus, was no longer operable since May 2010. Even though there weren’t any STOP operations, the statistical tests show significant reductions in the crash rates at certain control intersections for certain crash types. Our study also includes a total of 38,169 red-light violation records collected between March 2009 and February 2012. Descriptive statistics suggest that a majority of the red-light violations occurred during the daytime with two peak hours at 12 pm and 4pm, and the highest red-light violations occurred on Friday. The highest volume of the red-light violations occurred within 1 second after the onset of the red-light signal, whereas the second highest volume of the red-light violations occurred more than 3 seconds after the red-light signal. About 12,400 speeding violation records are also collected from five camera sites in the city between May 2010 and April 2012 for the violation analysis. The Lohman & Walnut westbound camera sites experienced the highest monthly average speeding violation counts whereas the Lobman & Teishor westbound recorded the lowest number. However, during the given study periods, the Lohman & Walnut westbound experienced a significant downward trend on it. There aren’t any significant changes on the monthly average speed of the vehicles at the time of the violations.
Does anyone know whether they have all "all red" interval between light changes?
Adjust the yellow timing
We often hear from many that adjusting the yellow light length will reduce the number of red light violations. Well, the following quote from the US Department of Transportation sees it differently:
Yellow interval duration. Both long yellow intervals which can violate driver expectancy and short yellow intervals (intervals shorter than the Institute of Transportation Engineers (ITE) - suggested values) have resulted in a high number of RLR violations.
(http://safety.fhwa.dot.gov/intersection/resources/fhwasa1000...)
But just how long should the yellow be lit? The same document provides the currently accepted formula for yellow light duration. For a posted speed limit of 30 MPH, the light should be yellow for 3.2 seconds. At 35 MPH, the yellow should be on for about 3.6 seconds and at 45 the time is 4.3 seconds. That's pretty close to the 1 second per 10 MPH rule of thumb. All this assumes the road is level.
The New Mexico report also talked about speeding which was omitted from The Newspaper report. The two posted speed limits were 35 and 40 MPH. That means the yellow should have been on for approximately 3.5 and 4 seconds respectfully. Before you state raise the speed limit, consider the higher speeds were in one direction only and the majority of the tickets were issued during daylight hours with the peak times between 10Am and 6PM.
Illiterate? Write for free help.
The report had Preliminary Conclusions
which were:
5. PRELIMINARY CONCLUSIONS
The following preliminary conclusions can be made:
The trend analysis of the signalized intersections shows some changes in the crash rates at certain intersections for certain accident types. Even though some of findings from the crash data are encouraging, not all the results from the trend analysis are supported by the statistical analysis.
• Descriptive statistics suggest that the program has a positive impact on the traffic safety at the LOTE camera intersection. The introduction of the STOP at the LOTE intersection reduces the total crash rates, mainly due to the reduction on the rear-end crash rates and the property-damage only crash rates.
• The Lohman & Walnut intersection experienced an overall, negative impact. After the STOP operation, there were significant increases in every category of the crashes. The Main & Solano intersection also experienced an overall, negative impact as a result of the STOP operation. After the camera was installed, the trend has an upward spike after which the rates remain steady until the deactivation, when they trend downward quickly indicating a negative effect made by installing the camera.
• The VAAM camera intersection showed a mixture in reduction and incremental rates. However, we cannot make a solid conclusion on the camera effect at the Valley & Avenida de Mesilla intersection. This is because the northbound camera is still operable while southbound camera had deactivated and thus, was no longer operable since May 2010.
• Even though there weren’t any STOP operations, the statistical tests show significant reductions in the crash rates at certain control intersections for certain crash types.
• The highest volume of the red-light violations occurred during the daytime with two peak hours at 12 pm and 4pm, and the highest red-light violations occurred on Friday.
• A majority of the red-light violations occurred within 1 second after the onset of the red-light signal, whereas the second highest volume of the red-light violations occurred more than 3 seconds after the red-light signal.
• Red-light violation did not decrease in any of eight camera sites since starting the STOP program.
• Significant decrease in speeding violation has been observed in 4 of 5 camera sites during the two years of study period. LOTE-EB, LOTE-WB, LOWA-EB and LOWA-WB showed downward trend since May 2010.
• The LOWA-WB experienced the highest monthly average speeding violation counts whereas the LOTE-WB recorded the lowest number. Both LOWA-WB and LOWA-EB camera sites experienced a significant downward trend on the average monthly speeding violations. Also, slightly downward trends are observed at the LOTE-EB and LOTE-WB camera sites. The VAAM camera site shows a flat trend, overall.
• There aren’t any significant changes on the monthly average speed of the vehicles at the time of the violations.
My opinion is that it was fair for thenewspaper.com to state that the study finds "no clear" red light camera benefit. That is very good for them because they are usually very misleading - cherry picking comments to cast cameras in the worst light possible.
agree
which were:
5. PRELIMINARY CONCLUSIONS
The following preliminary conclusions can be made:
The trend analysis of the signalized intersections shows some changes in the crash rates at certain intersections for certain accident types. Even though some of findings from the crash data are encouraging, not all the results from the trend analysis are supported by the statistical analysis.
• Descriptive statistics suggest that the program has a positive impact on the traffic safety at the LOTE camera intersection. The introduction of the STOP at the LOTE intersection reduces the total crash rates, mainly due to the reduction on the rear-end crash rates and the property-damage only crash rates.
• The Lohman & Walnut intersection experienced an overall, negative impact. After the STOP operation, there were significant increases in every category of the crashes. The Main & Solano intersection also experienced an overall, negative impact as a result of the STOP operation. After the camera was installed, the trend has an upward spike after which the rates remain steady until the deactivation, when they trend downward quickly indicating a negative effect made by installing the camera.
• The VAAM camera intersection showed a mixture in reduction and incremental rates. However, we cannot make a solid conclusion on the camera effect at the Valley & Avenida de Mesilla intersection. This is because the northbound camera is still operable while southbound camera had deactivated and thus, was no longer operable since May 2010.
• Even though there weren’t any STOP operations, the statistical tests show significant reductions in the crash rates at certain control intersections for certain crash types.
• The highest volume of the red-light violations occurred during the daytime with two peak hours at 12 pm and 4pm, and the highest red-light violations occurred on Friday.
• A majority of the red-light violations occurred within 1 second after the onset of the red-light signal, whereas the second highest volume of the red-light violations occurred more than 3 seconds after the red-light signal.
• Red-light violation did not decrease in any of eight camera sites since starting the STOP program.
• Significant decrease in speeding violation has been observed in 4 of 5 camera sites during the two years of study period. LOTE-EB, LOTE-WB, LOWA-EB and LOWA-WB showed downward trend since May 2010.
• The LOWA-WB experienced the highest monthly average speeding violation counts whereas the LOTE-WB recorded the lowest number. Both LOWA-WB and LOWA-EB camera sites experienced a significant downward trend on the average monthly speeding violations. Also, slightly downward trends are observed at the LOTE-EB and LOTE-WB camera sites. The VAAM camera site shows a flat trend, overall.
• There aren’t any significant changes on the monthly average speed of the vehicles at the time of the violations.
My opinion is that it was fair for thenewspaper.com to state that the study finds "no clear" red light camera benefit. That is very good for them because they are usually very misleading - cherry picking comments to cast cameras in the worst light possible.
Common sense. Ask MD or DC if red light and speed cams have any relevance?
I can't tell you how many intersections I pass through on my commute to work, where, when the light turns green, folks have to wait for 4-6 cars to run the intersection on red, before proceeding. does a rlc change that? You bet.