1950s: Cars and Smog
Air pollution and cars were linked in the early 1950s by a California researcher who determined that traffic was responsible for the smoggy skies over Los Angeles. Since then, the California and Federal governments have set standards to bring down levels of these pollutants. The auto industry has responded by developing new emissions control technologies.

1966 – 1970: Clean Air Act
Even before the first Clean Air Act (CAA) of 1970, California required minimal emissions controls on 1966 model cars. Congress followed suit in 1968 and required similar controls on 1968 and newer cars. Two years later, Congress called for a 90 percent reduction in automotive emissions and directed the United States Environmental Protection Agency (USEPA) to establish health-based standards for six criteria pollutants, all of which are present in auto exhaust to some degree^I.

1970-1975: Early Emissions Controls
During this period, emissions control technologies such as charcoal canister traps, exhaust gas re-circulation valves, catalytic converters, and the corporate average fuel economy (CAFE) program appeared. ESP’s founding company, Hamilton Test Systems (a division of United Technologies) started the first I/M program in Arizona in the mid 1970s.

1975-1983: I/M Emerges – Total Fleet Exhaust Emissions Testing
By 1983, responding to legislative mandates and spurred by Arizona’s early success, 64 cities followed suit with I/M programs. Nearly all programs used an idle emissions test for Hydrocarbons (HC) and Carbon Monoxide (CO). ESP, through its founder Hamilton Test Systems, was a principal supplier of products and services.

Late 1980s: I/M Converts to Loaded Mode Testing
By the late 1980s it became apparent, as automotive technology was advancing, that idle testing was not only inadequate for modern vehicles, but was also only marginally effective at identifying malfunctions that contribute to elevated emissions during typical driving cycles. The USEPA also recognized that loaded mode testing would be necessary to identify excess emissions in newer technology vehicles.

These two years of congressional legislation and agency ruling were a turning point in the industry. Centralized (test only) inspection had taken hold, loaded mode tests represented the future of I/M testing, and remote sensing received its first enabling legislation. Once again ESP was at the forefront of these significant changes. Envirotest, ESP centralized testing services predecessor, quickly became the dominant U.S. centralized provider. RSTi, a wholly owned subsidiary of Envirotest, commercialized remote sensing with the introduction of its patented Accuscan technology. ESP became a leading supplier of loaded mode test equipment. This was only the beginning of ESP’s influence on the industry.

1990-1992: CAA Amendments – Transient Mass Emissions Test and RSD Emerge
Although mandated emissions controls and improving fuel efficiency had contributed to significant automotive emissions reductions through the 1980s, the number of vehicle miles traveled had nearly doubled in the US and existing I/M programs had not produced the desired emissions reductions. Congress once again intervened, by enacting the 1990 Clean Air Act Amendments (CAAA) calling for "enhanced" testing in areas with the worst air quality. The USEPA responded with guidelines for a 240 second transient loaded mode test known as IM240 and prescribed a centralized test network to identify the most excess emissions. The mandate was challenged by many states. States demanded flexibility to develop their own I/M tests and design their own I/M networks. States argued that the USEPA should only prescribe the END (the health-based standard that must be achieved) and that States should be free to develop the MEANS (the I/M test and network most suited for their economies). Congress made one more significant mandate in the CAAA which led to the USEPA rule that all "enhanced" areas should test 0.5% of their fleet using an on-road testing technique, such as remote sensing devices.

1992-1995: RSD Studies – Hybrid I/M
Overwhelming resistance to centralized (test only) IM240 soon led the USEPA to offer states flexibility to adopt equivalent I/M tests and program designs. California took the lead by developing the ASM test and designing a unique decentralized program that included a percentage of test-only inspection facilities. California also proposed remote sensing-based gross emitter identification as a supplement to its I/M program. Suspected high emitters would be directed to the special certified test only facilities for an off-cycle emissions inspection. Studies conducted by the California Air Resources Board (CARB) demonstrated equivalence to IM240 and the hybrid program including remote sensing was submitted as part of California’s emissions reduction plan. So was born the concept of on-road screening using remote sensing technology. The USEPA studied Accuscan technology in Arizona and California and recognized the supplemental benefits of RSD screening. By the mid-1990s, enhanced areas with deteriorating air quality, eager to supplement their I/M programs, began pressuring the USEPA to release a formal guidance on RSD-based gross emitter identification. Even before the guidance, California and Arizona began large-scale pilot investigations to determine how best to integrate RSD into their respective I/M programs. Again, ESP’s predecessor companies provided the remote sensing technology, the data collection services, and the consultation to both California and Arizona in these landmark pilots.

1996-1998: Gross Emitter Guidance
In September 1996, before the results of the Arizona and California pilots were available, the USEPA released its first remote sensing guidance (EPA420-R-96-004) based on the earlier California and Arizona studies^II. Texas was one of the states struggling with deteriorating air quality. In 1998, Texas launched the first enforceable gross emitter program. Colorado, however, was in a different situation. They had started centralized (test only) IM240 with Envirotest in 1994 and were now experiencing improving air quality. So they began exploring the use of remote sensing to identify clean vehicles that could be exempted from the centralized IM240 test. RSTi was contracted to conduct both the landmark Greeley and Denver clean screen pilot studies.

1998-2001: Clean Screen Guidance
By late 1998, the USEPA released the second remote sensing guidance on clean screening (EPA420-P-98-008), based on RSTi’s study results^III. Just as gross emitter identification had become the favorable I/M program supplement for increasing excess emissions identified, clean screening was becoming a favorable means of reducing the burden of I/M for vehicles that did not produce excess emissions. In 1999, Missouri was facing its own air quality challenges and needed a new I/M design. ESP worked closely with the Missouri Department of Natural Resources (MDNR) to develop a clean screen program in combination with a smaller centralized (test only) IM240 network that would suit MDNR’s overall automotive emissions reduction plan. In April 2000, Missouri started the first clean screen program in the US. Although, Colorado had pioneered the clean screen concept, a lengthy political process delayed formal implementation and it became the second clean screen program. ESP began remote sensing data collection in Greeley, Colorado in March 2001.

Texas had effectively deferred an I/M program expansion by introducing gross emitter identification in 1998. However, increasing mobile source pollution required an expansion of its I/M program area as well as a transition to loaded mode testing. By the transition date of May 2002, ESP will have supplied the majority of the new ASM loaded mode emissions test systems to Texas decentralized garages and By the end of 2003, ESP will have expanded the gross emitter program from 4 counties to 15.

2002: Program Evaluation Guidance – Diesel and Gasoline Screening Approaches
ESP is the largest and most experienced I/M solutions provider in the world and the only provider of comprehensive remote sensing screening services. Last year, we released our fourth generation Accuscan technology that features smoke/particulate measurement capability. We have conducted trials in Austria (with the Budesprufanstalt fur Kraftfahrzeuge, Austria’s vehicle testing agency) and in Japan (with the Tokyo Metropolitan Government and the Ministry of Land Infrastructure and Transport) on heavy-duty diesels, as well as gasoline vehicles, and have demonstrated roadside enforcement activity to the United Kingdom’s Vehicle Inspectorate.

As if the formal recognition of gross emitter and clean screening were not enough to reshape the industry, the USEPA is poised this year to release its third guidance on remote sensing. This time it will formally recognize the third and arguable the most powerful application of remote sensing. All enhanced areas are required to quantify the emissions reductions of their I/M program biennially. Since 1998, there have only been three methods formally approved by the USEPA for I/M program evaluation, none of them proving very effective in implementation^IV. Today, once again with the help of data collected with Accuscan technology and the input of ESP experts that comprised the core group responsible for drafting the guidance, the USEPA is ready to formally recognize remote sensing-based program evaluation. Even in advance of its release, Virginia, facing a program change like Texas, hired ESP to conduct a baseline evaluation of its decentralized program before those anticipated changes in 2003. ESP will deliver its evaluation report along with its recommendation for program design in the beginning of 2003. Just this month, Virginia passed legislation that authorizes a gross emitter supplement, making Virginia the likely second large-scale gross emitter program in the United States and the fourth large-scale screening program of its kind.

The National Academy of Sciences was recently commissioned by Congress to evaluate the state of the US I/M industry. The NAS concluded "by expending too many resources to inspect "cleaner" low-emitting vehicles, coupled with a lack of effective ways to deal with the dirtiest ones, states are missing opportunities to reduce air pollution". Since "older and malfunctioning vehicles, that usually make up about 10 percent of the nation's fleet, typically emit about 50 percent of most harmful air pollutants from motor vehicles," the NAS reported that these gross emitters "should be the primary target of state emissions I/M programs if they are to achieve any real progress in reducing vehicle emissions."^V