Can the state achieve the same air pollution reduction from a stand-alone roadside auto emission testing program (the roadside testing vans) that it currently achieves through its combined program using stationary testing centers and the roadside testing vans?
Following a thorough assessment, including one by the state auditor, the answer is no.
The nine-county Front Range area currently is out of attainment with the federal health-based ozone standard, which is expected to be tightened even more this summer.
Developing the most cost-effective auto emission reduction strategies that will bring Colorado into compliance with federal health-based ozone standards has both costs and benefits that must be carefully, openly and honestly assessed relative to other potential strategies.
In 2006, the state legislature passed House Bill 1302, directing the department to consider the viability of a stand-alone roadside auto emission testing program to identify high-emitting vehicles.
In response, the Air Pollution Control Division of the Colorado Department of Public Health and Environment implemented the largest high-emitter auto emission program study ever undertaken anywhere in the world. Data from the three-year study established that while the roadside equipment can effectively identify some high-emitting vehicles, the overall benefit of a stand-alone roadside program was far less than the approximately 15 tons per day reduction of ozone-causing emissions achieved in the Denver area by the current centralized station-based program.
The Office of the State Auditor, in its own independent analysis of the department’s study, reached the same conclusion, stating that “the department cannot use a Rapid Screen (roadside) high-emitter program to replace the current traditional emissions test and the Rapid Screen ‘clean screen’ component of the program as intended by HB06-1302. Further, technology does not currently exist that would reach the ultimate goal of HB06-1302.”
Just to clarify, the roadside vans are equipped to do two types of emission testing. First, the test can identify “clean cars” that do not then have to go to a testing center. Second, roadside testing can identify “high pollution emitters” that do require additional testing at a testing center. However, the department’s study found the roadside testing for “high emitters” was effective in identifying “clean” cars, but not effective in identifying all vehicles that would fail traditional emissions testing. The roadside vans only could observe a fraction of the vehicle fleet that is otherwise tested, and there were problems consistently identifying only the truly dirty cars. Thus dirty cars missed by roadside testing would be left on the road, if not for the state requirement that cars not passing the clean-screen be tested once every two years at a testing center.
Proponents of a stand-alone roadside testing program fail to present realistic scenarios for implementing an effective replacement for the current program. Absent a traditional testing center, the concept of pulling over and impounding high emitting vehicles that fail roadside testing is impractical, and to begin to observe enough vehicles in the total fleet in the nine-county area would require a dramatic and unrealistic expansion of roadside vans with program and cost effects. These are not options the state supports.
The department fulfilled its legislatively directed obligations to assess this roadside technology and concluded that a stand-alone roadside testing program is insufficient to obtain the necessary air pollution reductions needed to meet EPA ozone standards. The department will continue to look at future auto emission reduction strategies that help reduce harmful emissions in the state as it prepares a state plan for the upcoming federal ozone standard.
Chris Urbina is executive director and chief medical officer for the Colorado Department of Public Health and Environment. Paul Tourangeau is director of the CDPHE’s director of Air Pollution Control Division.
