August 18, 2000 UNT Inhouse publication: Vehicle inspections have little impact, researcher finds

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Vehicle inspections have little impact, researcher finds

The state of Texas' 10-year-old vehicle inspection and maintenance program has resulted in little decrease of ozone levels in most of the state's urban areas that violate air quality standards set by the Environmental Protection Agency, according to a UNT resear photo of Al Bavon cher.

Al Bavon, assistant professor of public administration, gathered monthly ozone data from January 1987 to October 1997 for Dallas-Fort Worth, Houston-Brazoria-Galveston, Beaumont-Port Arthur and El Paso. The inspection and maintenance program is required in these areas, which exceed hourly EPA levels for ground-level ozone, or smog. These areas accounted for half of the state's population in 1998, Bavon says.

According to the EPA, approximately 35 percent of all man-made volatile organic compounds and nitrogen oxide, which are major contributors to smog, result from motor vehicle emissions. In addition, approximately 65 percent of all man-made carbon monoxide results from motor vehicle emissions.

Because inadequate maintenance of motor vehicles and illegal use of leaded gasoline result in more vehicle emissions, Texas began the inspection and maintenance program in 1989, in accordance with the federal Clean Air Act. Gasoline-powered vehicles that are less than 25 years old are tested annually for emissions and safety beginning when the vehicle is two years old.

Although all the areas showed monthly decreases in ozone levels over that period, the decreases were very small, ranging from 0.000145 parts per million in Beaumont-Port Arthur to 0.00310 parts per million in Dallas-Fort Worth. Dallas-Fort Worth had the only statistically significant decrease, Bavon says.

He notes that lack of significant decreases in ozone in Beaumont-Port Arthur, El Paso and Houston-Brazoria-Galveston could be attributed to other sources of pollution that emissions testing equipment is unable to control. For instance, a primary industry in Houston-Brazoria-Galveston and Beaumont-Port Arthur is petrochemicals, Bavon says.

Dallas-Fort Worth, on the other hand, does not have this type of industry, and it was the first area to use TX 96 inspection equipment, "which is designed to capture more pollutants than the old equipment," he says.

He adds that Dallas-Fort Worth was the first area to allow motorists to have their vehicles inspected at a station of their choice.

However, beginning in November 1994, the state implemented a centralized system for inspection, requiring all vehicles to be inspected at a designated station. The centralized system was scrapped in favor of the motorist's choice system six months later.

"Florida and California have used the centralized system, operated by private companies, for many years," Bavon says. "It has its problems because people must often drive a long way to go to the centralized inspection station. However, the decentralized system we have today can be subject to abuse."

Privately owned automobile maintenance facilities must have licenses to conduct state inspections, but "there is relatively little or no monitoring of the thousands of people who conduct the tests," Bavon says.

"The fact that vehicle inspection has not drastically reduced ozone levels is a reflection of the state's inability to scrap the decentralized system," he says. "And our current approach is not very effective."

Bavon's study was published in Forum of the Association for Arid Lands Studies, 1999. He plans to continue the research by comparing pollution levels in areas with a vehicle inspection program to areas without a program, controlling for other variables including mean temperature, relative humidity, number of motor vehicles and vehicle miles traveled.