Accidents more than doubled at the Houston, Texas intersections where red light cameras are installed, according to a study released Monday by Rice University and the Texas Transportation Institute (TTI). This result posed a dilemma for TTI and the city of Houston which had requested the study.

Houston Mayor Bill White was furious when he saw the report’s draft text in August. He banned the document from publication and ordered a re-writing of the text that would reflect a more positive result. To accomplish this task, White was able to turn to the study’s primary author, Rice University Urban Politics Professor Robert Stein. Stein’s wife, Marty, is employed by the city of Houston as a top aide to the mayor. Stein’s newly revised report now concludes that “red light cameras are mitigating a general, more severe increase in collisions.”

That left the Texas Transportation Institute with its own difficulty. Last month TTI coauthored another study with the Texas Department of Transportation (TxDOT) intended to support photo enforcement on a statewide basis. This report drew its conclusions from an examination of 56 intersections, 31 of which were found in Houston. The TxDOT-TTI study received wide publicity for the reported claim that red light cameras reduced accidents at camera intersections by 30 percent ( view study in 1mb PDF format).

“The TxDOT-TTI results are impossible to square with Houston’s results,” Houston attorney Randall L. Kallinen told TheNewspaper.

Kallinen and attorney Paul Kubosh have filed a lawsuit to force Houston to disclose the August draft of the Rice-TTI study under state freedom of information laws. Publicity over the lawsuit likely forced the city finally to release the final report during a holiday week. The revised report’s data tell a much different story than that presented in the conclusions.

Houston currently tickets motorists at seventy intersections, but the Rice-TTI report examined the first fifty where the most accident data were available. Beginning in September 2006, Houston commissioned American Traffic Solutions to install the machines in groups of ten per month. The Rice-TTI study compared 24 months of pre-installation data to between 13 and 21 months of post-installation data for each of the five groups. According to TheNewspaper’s analysis of overall accident data found in the appendices, the average number of monthly collisions went from an average of 15.4 collisions per month in the two years prior to camera enforcement to 58.3 accidents per month in the post-installation period. Although this figure is not reported in the study itself, the general fact is briefly acknowledged.

“The absolute number of collisions at camera-monitored intersection approaches is not decreasing,” the study admitted.

To achieve the appearance of success, the study divided red light camera intersections into “non-monitored” approaches — the directions of travel at the intersection where the red light camera is not looking — and the “monitored” approaches where ticketing took place. There was a 132 percent increase in collisions at the non-monitored approaches of the intersection where red light cameras were installed and a non-significant nine percent increase at the monitored approaches. The study treated these increases in both rear end and T-bone collisions as unrelated to the red light camera as long as the accident happened outside of the camera’s view.

The study concluded that because the accidents went up at the non-monitored approaches of red light camera intersections, but effectively stayed the same at the monitored approaches, that the red light cameras were responsible for the “benefit” (a smaller increase) at one part of the red light camera intersection, but not the increase in accidents at the other. This line of thought would suggest that the increased accidents at the non-monitored approaches of red light camera intersections reflected an increase in accidents at the other city intersections that had no red light cameras at all. The study admits this implication is untrue.

“Currently, conclusions on a general increase in collisions across the city are not supportable with available data,” the study states.

The Rice-TTI dataset also throws doubt on the conclusions of the TxDOT-TTI study. Increases in Houston collisions documented by Rice-TTI mysteriously became decreases in collisions in the TxDOT-TTI report, as follows:

• Monroe at Gulf Freeway East Service Road: a 913% increase became a 41.7% decrease
• Hollister at Northwest Freeway: a 747% increase became a 60.5% decrease
• FM1960 West at Tomball Parkway: a 307% increase became a 44% decrease
• Richmond at Dunvale: a 103% increase became no change
• South Sam Houston Freeway at Telephone Road: a 164% increase became a 19.3% decrease
• East Freeway North Service Road at Normandy: a 52% increase became a 25% decrease
• North Freeway West Service Road at West Rankin Road: a 18% increase became a 32.7% decrease

In other cases, decreases became more pronounced and increases lessened. To cite just one example, a 217 percent increase in accidents in the red light camera approach of Scott Street at South Loop East North Service Road in the Rice-TTI report became a 50.1 increase in the TxDOT-TTI report. In general, far fewer collisions were reflected in the data used in the TxDOT-TTI report. Since Houston’s results comprised more than one-half of the statewide results, it is unclear how TxDOT and TTI could have concluded a statewide reduction in accidents without data manipulation in at least one of the TTI reports.

Source:  Evaluation of the City of Houston Digital Automated Red Light Camera Program (Rice Univeristy, Texas Transportation Institute, 12/28/2008), and The Newspaper,  Houston Red Light Camera Report Undermines TxDOT Camera Study (republished with permission)

Red-light cameras, which have split the driving public like few other topics of the road, are reaching a public opinion crossroads.

Texas cities have collected more than $103 million in fines since a revised red-light camera law took effect in 2007. Houston has collected the largest chunk: some $24 million through May, state figures show.

Cities insist the cameras have cut intersection accidents and saved lives. But the rising revenue totals have fueled a public backlash and reinforced perceptions that their main impetus is money.

Lawmakers in Maine, Mississippi and Montana banned red-light cameras last year, according to the National Conference of State Legislatures. Six other states recently considered similar proposals.

In Texas, College Station voters last fall forced their city to take down its cameras. Houston opponents say they have enough petition signatures to put the cameras to a vote this fall. And the Texas House of Representatives last year passed a measure that would have phased out the cameras. Though it failed in the Senate, camera opponents say they plan to try again.

“There is a backlash, for sure,” said state Rep. Solomon Ortiz Jr., D-Corpus Christi, who co-sponsored the anti-camera push. “City budgeters are counting on these fines as a revenue stream and simply using the argument of safety as cover.”

That sentiment clashes with the opinion of many engineers and city officials who say the cameras have, unequivocally, improved intersection safety.

The cameras capture images, and sometimes video, of drivers running red lights. The images are vetted by the camera company and, ultimately, by police. Most Texas cities charge civil fines of between $75 and $100 per violation. More studies than not suggest the cameras work, at least to some degree.

“They’ve performed much better than I ever imagined,” said Elizabeth Ramirez, chief traffic engineer for Dallas. The city has witnessed declines in red-light accidents at nearly every one of its 59 camera-equipped intersections since the first wave launched in January 2007, she said.

While camera critics dispute the safety data, the money generated has raised even more questions and intrigue, especially as collections have pushed into the tens of millions. A 2007 state law requires cities to set aside half of all profits to help fund regional trauma care centers. Most cities use their share for traffic safety and enforcement efforts.

Houston police Sgt. Michael Muench, who oversees that city’s red-light camera program, said his department has plowed all revenues into crash-scene investigation equipment, extra traffic patrols, radar guns and other traffic-related improvements. “So far, it’s working,” Muench said. Critics point to large disparities in the profits cities generate as evidence that some are just out to make a buck.

“In College Station, cameras were not put at the most dangerous intersections, but the most profitable ones,” said Jim Ash, a sales representative who began the petition drive to take down the cameras there.

In fact, the contracts that cities have with camera vendors are the biggest factor in whether or not a city makes money, according to an analysis of state figures and the vendor agreements of about a dozen Texas cities. Cities do not purchase, operate and maintain the equipment outright. Rather, they rent the cameras from vendors under negotiated terms. Houston’s $24 million haul since 2007 is more than triple the total fines collected by Dallas, according to figures from the state comptroller’s office. And in the last two years, Dallas’ program has cost more to run than Houston’s.

That is because Houston pays a flat monthly fee of $3,000 per camera, plus bonuses if a camera catches a high number of violations. In contrast, Dallas pays its vendor $3,800 per camera per month. Houston, which has 70 cameras, uses American Traffic Solutions Inc., of Arizona. Dallas, with 59 cameras, uses a hometown contractor, Affiliated Computer Services.

Garland, which also uses ACS and is believed to be the first city in Texas to install the cameras, has run a deficit in its program that once reached almost $300,000. The city has gradually paid back the contractor with red-light camera funds.

George Kauffman, Garland’s finance director, suggested the shortfall proves that the city’s goal has never been profit. He also argued that Garland’s 12 cameras have proven so effective that the program now collects fewer fines than before.

“We’re trying to do it for the right reasons,” he said. “As long as we’re breaking even and taking care of our costs, then we’re happy.”

The city’s less-favorable camera contract, however, has played a big role in the financial difficulties. Garland pays ACS nearly $5,000 a month per camera. The city also is paying ACS for the installation of three extra cameras in 2008. Most cities do not pay for installation.

All told, Garland is paying twice as much to operate some of its cameras as Houston. Kauffman noted that Garland, as one of the first to install cameras in 2003, had fewer vendor options than Houston.

Houston’s larger collections, of course, have led to public resistance and the petition drive to repeal the cameras.

Paul Kubosh, a Houston traffic attorney who has led the petition drive, accused the city of “selling the streets to the highest bidder. It’s a voter revolt.”

Jim McGrath, a consultant who works for a group tied to Houston’s camera vendor, American Traffic Solutions Inc., said red-light cameras are easy targets for criticism. After all, he said, they raise the specter of Big Brother and “are something everyone can identify with.”

But he added, “If these cameras were catching child molesters, we would insist on having them on every corner. … Critics who say this is just a money grab are really saying that the city of Houston is being too efficient at enforcing the law.”

• W/B Bay Area Boulevard @ El Camino Real
• W/B Bellaire Boulevard @ Wilcrest Drive
• N/B Brazos Street @ Elgin Street
• W/B Harwin Street @ Hillcroft Avenue
• E/B Richmond Avenue @ Hillcroft Avenue
• N/B John F Kennedy Boulevard @ Greens Road
• W/B Pease @ La Branch
• S/B Milam Street @ Elgin Street
• E/B Richmond Avenue @ Dunvale Drive
• N/B Travis Street @ Webster Street
• E/B Westpark @ Southwest Freeway, West Service Road
• Southwest Freeway, East Service Road @ Fountainview
• E/B Westheimer @ West Loop South, West Service Road
• East Freeway, W/B Service Road @ Uvalde
• S/B Sam Houston Parkway, South Service Road @ Beechnut
• W/B Bissonnet @ West Sam Houston Parkway South, East Service Road
• W/B FM 1960 West @ Tomball Parkway, East Service Road
• S/B Chimney Rock @ Southwest Freeway, West Service Road
• S/B South Gessner @ Beechnut
• S/E Hillcroft @ Southwest Freeway, West Service Road
• West Loop South, East Service Road @ San Felipe
• S/B Southwest Freeway, West Service Road @ Bellaire Boulevard
• S/B Southwest Freeway, West Service Road @ Beechnut
• N/B Southwest Freeway, East Service Road @ Fondren
• N/B Chartres @ St. Joseph’s Parkway
• W/B Bissonnet @ Southwest Freeway, East Service Road
• E/B El Dorado @ Gulf Freeway, East Service Road
• N/B Hollister @ Northwest Freeway, West Service Road
• E/B West Road @ North Freeway, West Service Road
• S/B North Wayside @ East Freeway, North Service Road
• S/B West Sam Houston Parkway South, West Service Road @ Bellaire Boulevard
• W/B Greens Road @ North Freeway, East Service Road
• N/B North Shepherd Drive @ North Loop West, South Service Road
• S/B Southwest Freeway, West Service Road @ Wilcrest
• N/B Main Street @ South Loop West, South Service Road
• W/B East Freeway, North Service Road @ Normandy
• W/B Monroe @ Gulf Freeway, East Service Road
• S/B Scott @ South Loop East, North Service Road
• N/B Antoine @ Northwest Freeway, West Service Road
• S/B North Freeway, West Service Road @ West Rankin Road
• N/B South Wayside @ Gulf Freeway, West Service Road
• N/B Woodridge @ Gulf Freeway, West Service Road
• W/B West Bellfort Avenue @ Southwest Freeway, East Service Road
• N/B Fairbanks-North Houston @ Northwest Freeway, West Service Road
• N/B West Sam Houston Parkway South, East Service Road @ Westpark Drive
• E/B FM 2351 @ Gulf Freeway, West Service Road
• E/B South Post Oak Blvd. @ West Loop South, West Service Road
• N/B Northwest Freeway, East Service Road @ Mangum Road
• W/B South Sam Houston Parkway East, North Service Road @ Telephone Road
• S/B Stella Link Road @ South Loop West, North Service Road
• E/B Bissonnet @ West Sam Houston Parkway South, West Service Road
• N/B Southwest Freeway, East Service Road @ Bellaire Boulevard
• S/B Tomball Parkway, West Service Road @ F.M. 1960 West
• N/B Chimney Rock @ Southwest Freeway, East Service Road
• W/B Westheimer @ West Loop South, East Service Road
• S/B West Loop South, West Service Road @ Westheimer
• W/B West Road @ North Freeway, East Service Road
• S/B Hollister @ Northwest Freeway, East Service Road
• N/B North Wayside @ East Freeway, South Service Road
• E/B East Freeway, South Service Road @ Market Street
• E/B Beechnut @ West Sam Houston Parkway South, West Service Road
• E/B Beechnut @ South Gessner
• N/B Wilcrest @ Southwest Freeway, East Service Road
• E/B Bissonnet @ Southwest Freeway, West Service Road
• N/B Hillcroft @ Southwest Freeway, East Service Road
• S/B West Loop South, West Service Road @ San Felipe
• W/B Richmond Ave. @ Dunvale
• S/B Woodridge @ Gulf Freeway, East Service Road
• S/B Southwest Freeway, West Service Road @ Fondren
• S/B West Sam Houston Parkway South, West Service Road @ Westpark Dr.

City Council also approved a five-year renewable contract with Scottdale, Ariz.-based Redflex Traffic Systems Inc. to install and operate a photographic traffic signal enforcement system at a minimum of four intersections — and up to 20 intersections — to record photographs and video of vehicles that run red lights.

Redflex will conduct an engineering survey to determine the intersections that warrant red-light cameras. Police Capt. Rickey Doerre said the Texas 249/FM 2920 and Texas 249/Zion Road intersections will probably rank among the top four to six that will be selected for the program.

Doerre said the council’s approval of the ordinance and the contract was the last step in a year-long study process conducted by the Police Department into the red-light enforcement system. The goal, he said, is to reduce traffic accidents by changing drivers’ behavior at those intersections.

“Hopefully it will be online in a six-month period, but that may be stretching it,” Doerre said. “The most important thing is that everything was approved tonight.”

The ordinance establishes rules and regulations for installing and operating the system, as well as a civil penalty of $75 for those convicted of a red-light violation, and the method for contesting alleged violations.

According to the contract, the system comes at no cost to the city. Redflex will pay to install and operate the system, and would garner up to $4,870 a month per intersection from fines paid to the city for red-light violations.

If the amount due to the company is not covered by the fines received by the city in a given month, that deficit amount will be carried forward and paid off through future surpluses.

Any additional revenue would be split evenly between the city and the Texas Department of Transportation, which owns the two major roadways — Texas 249 and FM 2920 — that traverse Tomball. The state’s share will be sent to the Texas comptroller’s office and deposited in a regional trauma account, and the city’s share will be utilized to fund traffic safety programs.

Lee Buckels, Redflex regional sales manager, said the company will work with the city and police department on a public awareness campaign about the camera system.

According to the contract, the company will issue all violation notices within two days of notification from the Police Department that a violation exists. A Tomball police officer will review all photographs to determine if the law was broken.

Violators would have access to photos through an Internet site, and all residents with questions will be able to call a toll-free number. A hearing officer or judge would handle contested cases.

After a year of red light camera use in Houston, Texas there is no evidence that the devices have saved lives.

One year after the installation of red light cameras, Houston, Texas Mayor Bill White declared the program a success, claiming the devices have led to a “dramatic decline” in the number of accidents. Further investigation by local television station KPRC suggests the ticketing devices may not have created such a clear-cut safety benefit.

A total of eighteen camera systems have been operating for the past year. KPRC compared the number of accidents one year before the devices were installed to one year after and found that ten intersections showed fewer collisions while seven showed an increase. In the case of the intersection of FM1960 and Tomball Parkway, the jump was a staggering 220 percent.

The number of accidents at a given intersection fluctuates from year to year so that a single year’s results can sometimes be misleading. This is especially the case when cameras are installed at intersections that, in one year, happened to have an abnormally high collision rate. A statistical error known as “regression to the mean” occurs when the natural drop in the number of accidents to a more normal level is ascribed to some other cause, such as red light cameras.

KPRC’s investigation also noted that cameras were installed in at least four intersections where collisions were extremely rare. Mayor White admitted factors other than safety went into the selection of camera locations. White promised a report in January that would show the benefits of the devices which have generated millions in revenue for the city.

View KPRC’s accident spreadsheet (18k PDF file).

Source: Do Red-Light Cameras Reduce Accidents? (KPRC-TV (TX), 11/20/2007)

That left the Texas Transportation Institute with its own difficulty. Last month TTI coauthored another study with the Texas Department of Transportation (TxDOT) intended to support photo enforcement on a statewide basis. This report drew its conclusions from an examination of 56 intersections, 31 of which were found in Houston. The TxDOT-TTI study received wide publicity for the reported claim that red light cameras reduced accidents at camera intersections by 30 percent.

“The TxDOT-TTI results are impossible to square with Houston’s results,” Houston attorney Randall L. Kallinen told TheNewspaper.

Kallinen and attorney Paul Kubosh have filed a lawsuit to force Houston to disclose the August draft of the Rice-TTI study under state freedom of information laws. Publicity over the lawsuit likely forced the city finally to release the final report during a holiday week. The revised report’s data tell a much different story than that presented in the conclusions.

Houston currently tickets motorists at seventy intersections, but the Rice-TTI report examined the first fifty where the most accident data were available. Beginning in September 2006, Houston commissioned American Traffic Solutions to install the machines in groups of ten per month. The Rice-TTI study compared 24 months of pre-installation data to between 13 and 21 months of post-installation data for each of the five groups. According to TheNewspaper’s analysis of overall accident data found in the appendices, the average number of monthly collisions went from an average of 15.4 collisions per month in the two years prior to camera enforcement to 58.3 accidents per month in the post-installation period. Although this figure is not reported in the study itself, the general fact is briefly acknowledged.

“The absolute number of collisions at camera-monitored intersection approaches is not decreasing,” the study admitted.

To achieve the appearance of success, the study divided red light camera intersections into “non-monitored” approaches — the directions of travel at the intersection where the red light camera is not looking — and the “monitored” approaches where ticketing took place. There was a 132 percent increase in collisions at the non-monitored approaches of the intersection where red light cameras were installed and a non-significant 9 percent increase at the monitored approaches. The study treated these increases in both rear end and T-bone collisions as unrelated to the red light camera as long as the accident happened outside of the camera’s view.

The study concluded that because the accidents went up at the non-monitored approaches of red light camera intersections, but effectively stayed the same at the monitored approaches, that the red light cameras were responsible for the “benefit” (a smaller increase) at one part of the red light camera intersection, but not the increase in acccidents at the other. This line of thought would suggest that the increased accidents at the non-monitored approaches of red light camera intersections reflected an increase in accidents at the other city intersections that had no red light cameras at all. The study admits this implication is untrue.

“Currently, conclusions on a general increase in collisions across the city are not supportable with available data,” the study states.

The Rice-TTI dataset also throws doubt on the conclusions of the TxDOT-TTI study. Increases in Houston collisions documented by Rice-TTI mysteriously became decreases in collisions in the TxDOT-TTI report, as follows:

• Monroe at Gulf Freeway East Service Road: a 913% increase became a 41.7% decrease
• Hollister at Northwest Freeway: a 747% increase became a 60.5% decrease
• FM1960 West at Tomball Parkway: a 307% increase became a 44% decrease
• Richmond at Dunvale: a 103% increase became no change
• South Sam Houston Freeway at Telephone Road: a 164% increase became a 19.3% decrease
• East Freeway North Service Road at Normandy: a 52% increase became a 25% decrease
• North Freeway West Service Road at West Rankin Road: a 18% increase became a 32.7% decrease

In other cases, decreases became more pronounced and increases lessened. To cite just one example, a 217 percent increase in accidents in the red light camera approach of Scott Street at South Loop East North Service Road in the Rice-TTI report became a 50.1 increase in the TxDOT-TTI report. In general, far fewer collisions were reflected in the data used in the TxDOT-TTI report. Since Houston’s results comprised more than one-half of the statewide results, it is unclear how TxDOT and TTI could have concluded a statewide reduction in accidents without data manipulation in at least one of the TTI reports.

Red light running is the leading cause of urban crashes according to the Insurance Institute for Highway Safety. In 2004, more than 900 people were killed and an estimated 168,000 were injured in crashes that involved red light running.

Houston-Galveston Area Council data indicate that red light accidents in the Houston area account for approximately $225 million per year in total comprehensive cost.

The City of Houston is committed to the safety of the community and dedicated to reducing preventable collisions at signalized intersections. Every year, there are thousands of crashes that occur due to motorists running red lights in Houston.

The City’s Red Light Camera Enforcement Safety Program uses state-of-the-art digital camera and detection systems installed at some of Houston’s most dangerous intersections for the purpose of decreasing the number of red light runners and reducing collisions.

• Affidavits
  - Individual Non-Liability
  - Law Enforcement Declaration of
  Non-Liability
• Frequently Asked Questions About the System (FAQs)
• Hearing Request
• How It Works
• Maps:
  - Red Light Camera Locations
• Red Light Camera Programs Do Affect Driver Behavior
• Red Light Running Facts
• What to do if you receive a Notice of Violation

To Contact Us:
Violation Processing Center
Houston Customer Service Center
Toll Free: 1-866-790-4111

Red-light cams: do they work?

Every few weeks, I receive calls from a man named Greg Mauz, a crusader against traffic cameras from Christoval, Texas. On his website, Mauz presents his arguments against red-light cameras.

Mauz wrote to me that red-light cameras are “entrapment for profit,” allowing governments to rake in ticket revenue while handing over a cut to the companies that install and maintain the cameras. Mauz and other critics also have constitutional and privacy objections.

Most provocatively, Mauz argues that red-light cameras make intersections more dangerous and cause more crashes.

I looked at some of Mauz’s papers and found his logic to be, at times, flawed. For instance, he adds together two percentages (on two different types of crashes) to make a new percentage to “prove” his point that the cameras increase crashes. But that’s an incorrect use of mathematics.

The city’s position — as articulated in its defense in a recent lawsuit — is that the cameras are effective and legal. They make driving more safe.

So who is right?

I decided to look at some evidence myself. A few things I learned along the way:

• Asking whether red-light cameras “work” depends on what you mean by work: Do they deter people from running red lights? (As measured by tickets issued) Do they cut the number of crashes? Injuries? Deaths? If a city decides to install the cameras, they need to be clear about what the criteria for “success” will be.
• Running red lights causes an estimated 100,000 crashes per year in the U.S., and 1,000 deaths (Federal Highway Administration). Texas appears to have the fourth-highest rate of red-light fatalities in the U.S. (Texas Transportation Institute).
• Red-light cameras are not the only way to change driver behavior at red lights. Increasing the duration of the yellow light by as little as one second can lead to a 50 percent reduction in red-light violations. (See the IIHS study, discussed below). Mauz is in favor of this technique.

Here are some studies I read closely. They differ in their scope and methods. I have abbreviated red-light cameras as “RLCs.”

Cochrane Collaboration (2005) [PDF]: This international panel combed through previous RLC studies, finding few (10 out of 30) that met its rigorous statistical criteria.* Conclusion: The cameras reduce crashes that cause injury, but “limited evidence” is “less conclusive” about whether the cameras reduce total crashes or traffic violations.

Federal Highway Administration (2005) [PDF]: A study of seven cities or counties using RLCs showed a decrease (25 percent) in right-angle crashes (“T-bones”) but an increase (15 percent) in rear-end crashes. Since right-angle crashes tend to cause more severe injuries, the net effect is that the cameras save money (as measured in medical care, quality of life, lost work productivity, etc.). The study actually put a price on it: $38,000 saved annually per red-light site.

Insurance Institute for Highway Safety (2007) [PDF]: This very small, short-term study looked at two intersections in Philadelphia. It examined the use of yellow-light timing and red-light cameras.

City of Garland, TX (2006) [PDF]: The city compared four intersections with RLCs with six “control” intersections without cameras. A “spillover” effect is suspected, as crashes decreased at all the intersections, but more so at the RLC sites (25 percent drop) than the controls (10 percent drop). Rear-end crashes increased at both types of intersections. But injuries from accidents decreased at the camera intersections; no data is given on injury rates at the “control” sites.

Houston-Galveston Area Council [PDF]: Red-light crash data from the eight counties in the greater Houston area, 1999-2001. There were 19,012 of these crashes in the three-year period, killing 128 people and injuring 26,847. Also contains a list of the top-15 intersections for red-light crashes (all are in Houston).

City of Houston red-light crash data (from H-GAC) [PDF]: Data from 1999-2001, but only for Houston. Shows that one-quarter of all red-light crashes in the entire state occur in Houston. No. 1 intersection for red-light crashes is Elgin @ Milam, with 113 over the three-year period.

Red-light cameras in Dallas, Plano and Garland [PDF]: The three cities, which also have installed systems, filed a “friend of the court” brief to support Houston’s defense in a lawsuit over the RLC program. This PDF contains copies of the three ordinances establishing the cameras in each city, and some short-term, preliminary data on crash reductions in Dallas and Plano (p. 8-9)

Whew! Thoughts on these studies? What criteria should the city use to measure if RLCs are working here? (Here’s a Washington Post investigation that criticizes the placement and effectiveness of D.C. red-light cameras). Should the city think about funding its own study?

– Carolyn Feibel

* The Cochrane report discusses important factors that can skew data, such as the “spillover effect,” in which red-light violations go down all over a city because of publicity about camera installation, and “regression to the mean,” a statistical distortion that occurs when cameras are installed at intersections with the highest violations, instead of at random intersections. Some of the other studies (and Mauz’s favorite studies) do not adjust for these effects. The Cochrane meta-study excluded all studies that did not deal with these data problems.

Posted by Carolyn Feibel at November 27, 2007 06:00 AM

Redlight Camera location map from the City Of Houston

Read the KPRC report on how there was more wreckes then before

the cammeras were added.

CLICK HERE

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