Traditional I/M programs were developed before the advent of remote sensing and before the accumulation of knowledge as to the emission-distribution pattern that exists in our automobile fleets. One cannot fault a regulation (or those who wrote it) for not being prescient, but one can question whether or not the requirements were short-sightedly closed to future developments in knowledge and technology.

Information regarding the ineffectiveness of traditional I/M programs and the skewed emission characteristics of the automobile fleet (Figure 3) have been accumulating for almost fifteen years, but this information has generally not influenced the evolution of the regulations. In fact, the EPA has expended far more energy in prescribing a sequence of new universal-testing technologies to replace previous universal-testing technologies than they have in exploring measures to refine the focus of testing in response to new information.

While the prime target for I/M—the small number of extreme emitters—has grown ever more clear, traditional I/M program requirements still focus on testing all vehicles, rather than only testing those that we have reason to believe are operating in an extremely polluting manner.

The lack of effectiveness of traditional I/M programs has been attributed to several technical phenomena, including inconsistent behavior of vehicle emission-control systems and post-test deterioration of emission control systems or system repairs. Others argue, however, that the biggest obstacles to success of traditional I/M programs are behavioral, resulting from the misguided incentives inherent in a system that revolves around the necessity of passing an annual (or biennial) test. Such programs generate incentives to "pass the test," but they do not create behavioral incentives for motorists to maintain clean vehicles year-round. As Charles Lave, an economist at the University of California, Irvine, puts it: "Such periodic testing is akin to a program that tries to "control" drunken driving by scheduling drivers for a breathalyzer test every two years." Traditional I/M programs also create incentives for fraudulent actions on the part of emission-test facility personnel, and for tampering.

Consider the incentives that motorists have faced under traditional I/M programs. They knew they’d face only an annual or biennial inspection and that there was a limit to how much money they might expend for repairs. They knew when the test was going to be, and they knew that they didn’t have to worry about any intervening inspections. Little save their own conscience motivated them to perform repairs until just before inspection time. In fact, a natural inclination to minimize expenditures on transportation favored putting off inspections and maintenance as long as possible—right up until the test date—at which time economic incentives favored finding a mechanic who could perform low-cost repairs to allow the vehicle to pass the test.

Mechanics and test-center owners also faced perverse incentives under traditional I/M programs in which they needed to provide quick and cheap certificates if they were to remain competitive. In the worst cases, this incentive led to cheating; audits of repair facilities show that a small percentage of shops specialized in providing fraudulent certificates or "quick fixes" that got the vehicle past the test without making any meaningful repairs.

Much of the data regarding I/M effectiveness was gathered fortuitously through an EPA program (begun in 1978) which actually was intended only to determine the rates and types of tampering and fuel switching prevailing after the 1977 amendments to the federal Clean Air Act. Other researchers re-analyzed this data in order to ask questions about I/M program effectiveness by program type, technology type, etc. Unfortunately, EPA’s nationwide tampering surveys ended in 1992, sharply curtailing our ability to continue tracking I/M programs with regard to effectiveness and efficiency.

Summary of efficiency considerations

In sum, I/M program efficiency has been sabotaged by a misguided focus on universal testing of light-duty vehicles in a hunt that includes even marginal emitters, despite an inability to guarantee improved performance of these vehicles through repair. Through their infrequent test regimen, traditional I/M programs create perverse incentives for motorists and mechanics, with no mechanism in place to validate I/M program performance on a continuing basis. Despite all of these uncertainties, EPA has traditionally spelled out I/M program requirements in detail, holding state programs answerable to complex computer models which define emission-reduction credits associated with the technology to be used in testing, the required frequency of testing, the population to be tested, and the certification procedures for repair facilities. 

B. Fairness

As recent events in California and elsewhere have demonstrated, fairness matters–perhaps as much as efficiency issues. For example, fairness issues have come to the fore in the I/M debate in the aftermath of California’s implementation of "Smog Check II," a compromise program worked out between the EPA and the state of California.

Information on the poor efficiency of traditional I/M programs has rarely reached the attention of the public (much less motivated them to take action). However, fairness concerns immediately arouse public attention. For example, the fairness ramifications of California’s Smog Check II were used by several northern California radio talk show hosts to mobilize large protests against the program. In part, what sparked the protests seemed to be the very program elements that could lead to greater I/M program effectiveness, including increases in repair-cost limits and a sharper focus on extreme-emitting vehicles.

Though Smog Check II suffers from a variety of flaws, California is at the forefront of efforts to reform I/M in a way that shifts the incentive structure faced by motorists to promote ongoing vehicle maintenance. The California hybrid I/M program incorporates a number of features intended to make it more efficient and equitable. The program eliminated waivers for extremely high-emitting vehicles. It raised repair-cost limits and instituted "between test" monitoring via a remote-sensing program. Its emphasis on shifting the inconvenience of centralized, IM240 testing onto only those vehicles that are probable high-emitters was an attempt to focus on problem vehicles, though this approach still has some significant problems.

While EPA’s preferred program featured annual testing of all vehicles at a small number of high-tech, test-only facilities, the California program tests only 15 percent of the California vehicle fleet this way, allowing the remaining 85 percent to be tested at either centralized test-only facilities or decentralized test-and-repair facilities. And to further refine the focus of the program on finding the highest-emitting vehicles, the 15 percent of vehicles required to go to test-only facilities are mostly (all but a two percent random sample) vehicles that have a high probability of being high-emitters, such as:

• High mileage fleet vehicles;
• Vehicles for hire;
• Vehicles identified as high-emitters by test/repair stations;
• Vehicles identified as likely high-emitters by remote sensing;
• Vehicles previously identified as high-emitters;
• Tampered vehicles; and
• Vehicles targeted through a high-emitter profile.

But demonstrations held on the Capitol steps in Sacramento showed that the public’s perception of Smog Check II differed strongly from that of planners and legislators, with the biggest sore spots involving issues of fairness, rather than efficiency.

Waving signs saying "First you took our guns, now you want our vehicles," and "USA not USSR," protesters objected to the prospect of high-cost vehicle repairs; the seemingly careless and motorist-unfriendly way that Smog Check II was implemented; and the possibility that their vehicle might become ineligible for registration, or even, through a much-exaggerated legal provision, subject to impoundment. While some of these objections had merit, especially those involving careless program initiation, technical glitches that failed certain types of new, perfectly functioning vehicles, and excessively tight cutpoints for others, many objections were based either on misconceptions of the program or on sentiments that directly contradict what the public has repeatedly said it wants—cleaner air and a robust Smog Check program. The matter of repair costs and their impact on low-income motorists was particularly worrisome, and indeed, the issue is a complex one. On the one hand, motorists have often emphasized the importance of personal responsibility for vehicle repairs. On the other hand, when confronted with potential economic hardship, the idea that individual motorists were to be held truly responsible for expensive repairs to their vehicle in response to Smog Check test failure seemed to strike many of the protesters as intrinsically unfair. This inconsistency could pose a problem more intractable than the formidable obstacles attached to technological improvement. 

0. Inappropriate Assumptions of Motorist / Vehicle Uniformity.

   The biggest inequity of traditional I/M programs is that they treat all vehicles and motorists essentially alike. Yet vehicles are not alike in terms of their pollution, and all motorists are not alike in terms of their mobility needs, behavior or income. Certain classes of vehicles are, in fact, extremely unlikely to be significant emitters. Some motorists might drive an older vehicle that produces more pollution per mile than a newer vehicle, but they might drive it much less, or at off-peak hours when their somewhat higher comparative emission level is also relatively less significant. Despite these obvious differences in vehicle and motorist behavior, most programs require that all motorists must still go through the inconvenience and expense (in terms of time and money) of taking their vehicle in for periodic testing. This inconvenience becomes even more burdensome under EPA’s initially proposed enhanced I/M program, in which a far smaller number of testing stations spread thinly over large urban areas were to test huge numbers of vehicles.

   When Colorado implemented enhanced I/M, wait times were as long as an hour, after a lengthy commute to the test-only facilities which, for property-value considerations, were located in suburban communities, rather than the more densely populated urban centers. And unlike the older test-and-repair shops, motorists could not simply drop their vehicle off for testing, but rather, had to sit and wait in their vehicle. While the wait time was eventually cut down (mainly by dint of creating "shorter" versions of the required 240 second test protocol), the distance and compulsory attendance problems remain. 

1. Mandates for Garage Operators.

Still another fairness issue that has surfaced recently involves the large number of small businesses that have to respond to the shifting technological requirements of I/M programs. Attempts to improve traditional I/M programs have led to changing requirements for complex equipment which, often, cannot be acquired as a simple upgrade to previously owned equipment. Such requirements for the purchase and use of specific types of increasingly expensive equipment often pose a challenge for small test-and-repair facilities. In other states, such as Colorado and Arizona (which simply accepted EPA’s proposed I/M program) this investment in equipment happens infrequently, with relatively long time periods for recouping the investment in dynamometer equipment through I/M fees. In California, however, attempts to make I/M more efficient and fair to the bulk of motorists has created an inequitable situation for repair shop operators. The prospects of more rapidly shifting clean air standards and the prospect of sinking large amounts of money into technology that may never pay for itself create a dilemma for repair shop owners who can’t be assured of recouping the costs of the last instrument investment before they’re required to implement a new one. This problem threatens to create a situation of de facto centralized testing by driving independent test-and-repair shops out of business through an ever-shifting set of technology mandates.

Even in regions that implement EPA’s enhanced I/M protocols without modification, the situation is tricky. High financial burdens on existing test and repair centers may lead many of them to avoid purchasing new, expensive test equipment, and to apply instead for re-certification as repair-only facilities. The prospect of this result raises the specter of centralized I/M testing becoming the only test facilities available, even where state regulators may have intended to maintain some test-and-repair facilities. A more flexible I/M methodology would allow for incremental modifications and some equipment flexibility, where feasible. 

Summary of Fairness Considerations

The central tenet of traditional I/M programs is also the central inequity—a focus on scheduled testing of all vehicles in the face of strong evidence that most motorists are driving comparatively clean vehicles that are not contributing much to our urban pollution problems. Another inequity embodied in traditional I/M programs is imposition of mandates on existing auto repair shops to comply with state-imposed protocols and to use costly, state-selected equipment that changes on an unpredictable basis unrelated to the economic pressures of the industry. Even programs that do focus on extreme-emitters, regardless of the technology used to identify them, face fairness problems and public disapproval. Too little attention has been given to public education and to finding methods to reconcile the interests of lower-income motorists while preserving the concept of individual accountability for disproportionate contributions to urban air pollution represented by high-mileage, extreme-emitting vehicles. 

Traditional I/M programs have been neither efficient nor fair. They do not produce incentives for motorists to drive cleaner vehicles, and they have not produced substantially cleaner air in the areas they serve even after attempts at reform. Adding insult to injury, traditional I/M programs have also inconvenienced the majority of motorists who drive clean vehicles. Reform is clearly called for.

And yet, there is still a need for: 1) motorists to perform necessary emission-system maintenance, 2) some mechanism that can tell a motorist when emission-system service is necessary, and 3) some mechanism that can insure that such maintenance is being performed. With sufficient reforms, I/M can fulfill these needs, providing an important component of automobility as it links personal freedom to drive with personal responsibility for preventing harms to others in the process. 

A. Erect a Clean-Screen and Focus on Finding Extreme-Emitters

A fairer emission-control system for automobiles would focus only on those who are operating their vehicles in a manner which harms others—i.e., by operating the small percentage of vehicles putting out extreme amounts of emissions. Reforms intended to achieve reductions in automobile fleet emissions must retain and refine this focus. One targets extreme-emitters because that’s where the emissions are. While this is easily said, however, it will take a dual-track approach to do it.

An important simplifying step would be to reduce the universe of vehicles that have to be tested by sophisticated means such as IM240 or BAR90, and the technology already exists to allow such a refinement in focus. Roadside remote-sensing technology that can be used to measure a vehicle’s emissions "on the fly" has been developed and extensively tested. While the technology isn’t necessarily ready to entirely supplant stationary testing of suspected extreme-emitters, it is clearly ready for use in distinguishing between clean vehicles and extreme-emitters, and it can make such determinations cheaply and efficiently for CO, HC, and even NOx. Other technologies that allow for greater motorist empowerment and even better discrimination between relatively clean vehicles and extreme-emitters also exist, or are in advanced stages of development. Early forms of on-board diagnostic systems (OBD) such as exhaust-gas oxygen sensors are already standard on new automobiles, giving motorists the ability to detect emission-system malfunctions as soon as they occur.

Concerns have been raised over the ability of remote-sensing to give good "coverage": that is, to "scan" enough passing vehicles to insure that the vast majority of extreme-emitters are detected, or, in a clean-screen scenario, to insure that enough clean vehicles would be scanned to allow the screening to benefit motorists and improve the program. Evidence gathered in a pilot study of remote-sensing equipment conducted in Sacramento should mitigate such concerns. In a study using several remote sensing units for about two months, 45 percent of the entire Sacramento metropolitan area vehicle population was measured at least once by the remote sensors. The implication of this pilot study is that even a single RSD unit operating every day for a year would test about 250,000 vehicles, compared to one IM240 unit’s ability to test only 19,000 vehicles if operated for 60 hours each week, 52 weeks each year, at a rate of six vehicles per hour. The feasibility of fielding an RSD-based clean-screen program has also been demonstrated in pilot projects in Ontario, Canada; Greeley, Colorado; and Phoenix, Arizona.

Incorporating remote sensing into I/M programs as a clean screen and extreme-emitter notification system would dramatically increase the program’s ability to evolve in response to:

• Changing vehicle fleet composition;
• Changing automobile-emission levels over vehicle lifecycles;
• Changing emission-control technologies;
• Changing emission-testing technologies;
• Changing motorist responses to clean-air incentives;
• Changing composition of vehicle fuels and fuel types.

In addition, as emission-control technology improves, a greater share of the remaining emissions comes from an ever-smaller number of high-emitters. Remote sensors are relatively inexpensive and are produced by private companies competing to produce higher-quality and lower-cost units. Upgraded units that are more sensitive and accurate can be introduced incrementally at relatively low cost to replace older technology models. Also, if pollutants rise or fall differentially (e.g., CO falls, but NOx does not) or some pollutants turn out to be more damaging to health than others (such as ozone or small particles), remote-sensing technology can be adapted to respond to changing ambient pollution levels, automobile-emission characteristics and motorist driving and maintenance behavior more readily than conventional I/M tests could.

In implementing a program using frequent but invisible remote sensing, certain infrastructure questions will have to be addressed. Remote-sensor siting will be one issue that requires careful consideration. In the city of Los Angeles Remote Sensing Pilot Project, sensor siting was found to be a nontrivial challenge. Physical requirements for sensor placement included:

• Sufficient traffic volume;
• Sufficient roadway length;
• Acceptable traffic congestion due to lane closures;
• Sufficient median area in roadways for the remote-sensing equipment; and possibly
• Sufficient area to conduct BAR90 and/or IM240 confirmation tests within a quarter-mile of the remote-sensing test area.

The report states that even in a city the size of Los Angeles: "In some planning areas of the city there were no sites which met both the physical requirements and the population cross section goals in the study." Those goals, essentially designed to assure that the tested population is representative of the overall vehicle fleet, would be the same in any broader implementation of remote sensing as a means of automobile emission monitoring.

Once the clean vehicles have been screened out, it will be easier to focus on finding and fixing extreme-emitters. In this regard, however, even the California I/M program, which goes farther in its efforts to identify extreme-emitters than many programs, may need further revisions. Currently, vehicles in California classified as "gross polluters" are identified on a self-referential basis—that is, classification as a "gross polluter" rests on a demonstration that a vehicle is emitting at some level higher than the original manufacturer’s specifications for that specific type of vehicle. Yet this definition has little relation to the more important distinction of which vehicles are contributing a disproportionate amount of emissions to the total on-road emissions inventory.

Figures 4 and 5 show the thresholds for a vehicle’s passing or failing the BAR-90 two-speed test and also show the thresholds for defining a vehicle as a "gross polluter."

These figures show how the self-referential nature of the current definition results in progressively cleaner vehicles being equally labeled as "gross polluters" despite the fact that a post-1993 "gross polluter" (see point "A" on figures 4 & 5) might be emitting only one-third the emissions of an early-1970s "gross polluter" (see point "B" on figures 4 & 5). In fact, vehicles less than 20 years old that fail I/M badly enough to be called "gross polluters" still produce only about half the emissions of a pre-1975 "gross polluter." Worse yet, a post-1980 vehicle can be designated a "gross polluter" despite having emission levels far lower than late 1960’s vehicles that pass the test (see points "C" & "D" on Figures 4 & 5). Despite the disparity in emission levels, "gross polluter" vehicles must all be repaired and retested in order to win certification.

The current self-referential definition results in far lower cost-effectiveness than would a standard based on repairing those vehicles which produce the majority of emissions–extreme-emitters–and those vehicles that are probably repairable, or at least repairable enough to justify the expenditure of resources.

Classification as an extreme-emitter should be based on the relative contribution to the pollution problem, not through reference to a vehicle’s variance from its ideal lowest-emission state. Since marginal emitters may not be repairable and if "repaired," may result in only small total emission reductions, states may wish to consider a program in which any vehicle that is not identified as an extreme-emitter should be considered clean enough, saving the majority of motorists the inconvenience of reporting for scheduled, stationary testing, the default option for any vehicle not clean-screened out of the program. Or, alternatively, only extreme-emitters might be categorized as "gross polluters," while other vehicles operating at emission levels only slightly above their manufacturer’s standard would simply fail as "non-compliant vehicles" requiring repair, but not requiring additional verification attendant upon identification as a "gross polluter." There is, of course, no "bright line" that determines what vehicles should qualify as extreme-emitters. In part, setting the extreme-emitter cut-off point would depend upon how much emission reduction one was attempting to achieve and which universe of vehicles were likely to actually be repairable. Also, such cut-offs might be revised over time as vehicles become cleaner and cleaner, should continued mobile-source emission-reductions be necessary.

B. Address the Economic-Hardship Problem

Any program designed to actually repair vehicles will raise serious fairness concerns involving repair costs, since high-emitters are often owned by those of limited means. Such motorists, in many cases, have little choice (in the economic sense) but to drive vehicles with high-emission characteristics.

In a study conducted for the City of Los Angeles, Nelson Sorbo and Ed Palen of Hughes Environmental Systems, Inc., makers of remote-sensing equipment, examined the socioeconomic characteristics of high-emitters identified during a study of remote-sensing feasibility. They found that:

• The average income of drivers of high-emitting vehicles was significantly less than that of motorists driving low-emitting vehicle. ($18, 365 vs. $36,508);
• 32 percent of the high-emitting vehicle drivers had an annual family income of less than $10,000. Only 13 percent of the low-emitting vehicle drivers had such low family income levels;
• 74 percent of the high-emitting vehicle drivers had a per capita income of less than $10,000. Only 37 percent of the low-emitting drivers had such low per capita income;
• 76 percent of high-emitting vehicle drivers felt that money was the major reason for not tuning up the vehicle.

The authors state that:

As California’s protests showed, such issues must be addressed in a manner that the public perceives as fair. A range of options is available to help minimize the inequities caused by virtually any change in existing governmental programs, especially transportation-related programs that consume a major share of low-income household annual income.

But this is tricky: subsidizing vehicle repair poses "moral hazard" problems, and actually may weaken the effectiveness of direct emission-charging schemes that states might implement. For example, instituting a system of subsidized auto repair would probably lead to generally higher rates for vehicle repair, as virtually all third-party pay systems have in the past. Also, program administration costs could mount as more motorists apply for assistance, requiring verification of economic need and appropriate use of whatever form of subsidy is given out. Subsidized repair would also create a perverse incentive for those who are marginally poor and who, by allowing their vehicle’s emission system to degrade far enough, can then qualify for free tune-ups and repair. Such systems invariably lead to fraud as people seek to gain free repairs of vehicle systems that they have neglected or that are only tangentially related to emissions.

Several approaches to this problem have been proposed, but few have been explored in any systematic way. Experience tells us that grant-based programs are unlikely to produce the desired results, while being prone to abuse. Loan-based programs, however, could address many economic equity concerns and minimize the potential for abuse while still putting the primary responsibility for driving a clean vehicle where it belongs, with the vehicle owner. As for who would administer such a loan program, a range of potential public-private partnerships can be envisioned:

• Private companies might advance repair funds for repair of high-emitting vehicles in exchange for some form of tradable emission reduction credit that could be used as an offset for more-expensive, less-effective incremental reductions on mobile or stationary sources of the same pollutants. Precedent for this approach can be seen in Hughes Aircraft Company’s program of employee remote sensing and subsidized repair, which was used to gain credit against emission reductions required under the now defunct Rule 1501.
• Banks and other lending organizations facing requirements for low-income community outreach might advance their interests while helping to clean the air by offering guaranteed loans to low-income motorists facing steep repair costs. This approach would require great care in determining eligibility, but other guaranteed-loan programs provide experience in dealing with the eligibility problem. Loan-guarantee funds might be raised through a variety of means including registration fee set-asides, revenues generated by publicly owned toll roads, or through the further development of high-occupancy/toll lanes, a form of limited highway pricing under active consideration in several states. 

C. Allow for Flexible and Economic Use of Appropriate Technologies

Efficiency considerations go beyond the question of simple effectiveness and also refer to getting the most "bang for the buck" spent on using I/M as an emission-control strategy. One of the most important changes to increase I/M system efficiency lies in reversing what EPA originally proposed as a central component of enhanced I/M: the requirement for extensive use of expensive, loaded-mode transient tests with failure criteria designed to fail vehicles that may be only marginally out of compliance and which might be impossible to repair at a reasonable cost. An efficient testing system would find vehicles with high levels of reducible emissions first, leaving marginal emissions of questionable repairability for last. It should favor spending money on repair, rather than testing, and thus should go with the cheapest test that meets accuracy requirements, rather than going with a more expensive test that does not outperform less-expensive tests at finding high-emitters. Both BAR90 and remote-sensing systems appear to offer such alternatives, if the focus is on extremely dirty vehicles and only on HC and CO emissions. BAR90 cannot be used to test for NOx failures.

Given that there is little difference in performance between centralized and decentralized I/M, in dynamometer or idle-test protocols for purposes of identifying extremely "dirty" vehicles (for CO and HC), and in the relationship between the facility where the vehicle is tested and the facility where the vehicle is repaired, logic would dictate that the cheapest of these alternatives would be preferable. This may vary by circumstance and over time. Some stations may find dynamometers to be preferable, since they can be used for many different purposes. Others may prefer idle tests, if only CO and HC need to be tested. Still others might favor only remote sensors. The various testing methods differ in their effectiveness at identifying various pollutants. For example, IM240 shows good ability to measure NOx. New generation remote-sensing devices also show good NOx-testing capability. In some cases, dynamometer testing may be the best method for the task at hand, such as in post-repair certification of vehicles classified as extreme-emitters. Within a given state or region, however, some level of uniformity might be desired by consumers facing the potential for conflicting "reads" by different types of equipment, even if the enforced uniformity comes at the cost of some efficiency.

Traditional I/M programs can improve their emission-reduction effectiveness further by allowing greater use of new emission-reduction technologies on old cars. Traditional I/M requirements often fail a vehicle on a "visual inspection" for having additional devices installed on the engine or emission-system even if those devices have been demonstrated to reduce vehicle emissions. This is nonsensical.

Efficiency also dictates avoiding needless spending and needless effort. EPA’s enhanced I/M structure requires tests for "evaporative emissions," pollutants that come off of the heated surface of the engine, or out of leaking engine seals, rather than out of the tailpipe. EPA estimates that evaporative hydrocarbon emissions account for 50 percent of all hydrocarbon emissions, but this oversimplifies the problem. Several studies have shown that the distribution of evaporative emissions is as highly skewed (if not more highly) than the distribution of tailpipe emissions. Other researchers studied "hot soak" evaporative emissions (emissions that evaporate after a vehicle’s engine turned off) and observed that only 20 percent of the study vehicles were responsible for 80 percent of the observed evaporative emissions. Also, requirements that a "purge test" be performed on vehicles that fail the evaporative emission test may cause damage to engines that could exacerbate the problem and raise the cost of repair. A more-efficient strategy would involve holding back such a costly test until it was clearly indicated, such as after identification of a vehicle as being a high tailpipe emitter, and therefore suspect in terms of maintenance history. 

D. Create Mechanisms to Assess and Improve I/M Program Performance

Traditional I/M programs were enacted without provision for performance measurement. While attributing specific reductions in air pollution to an individual component of a region’s air quality control program may be impossible, there are other ways to check the performance of an individual component. In the case of I/M programs, this could be accomplished by instituting random checks of emission control systems, performed voluntarily and non-punitively upon a representative cross-section of in-use vehicles. Such testing could be funded, as it was in the past, through Smog Check or other vehicle fees, which should cover the testing of 2,000–4,000 vehicles per year. 

E. Identify and Remove Legislative Obstacles

The federal Clean Air Act requires that some states implement prescribed I/M programs. These required programs consume a considerable portion of the state’s resources available for addressing automobile emission problems, thereby slowing down the development and testing of alternative control regimes.

EPA has announced its flexibility in helping states meet clean air standards. However, that flexibility has been limited to date.

Nonetheless, some progress has been made. The National Highway System Designation Act of 1995 imposed a moratorium on mandatory test-only IM240 programs, and further, allowed states to propose an interim I/M program and required that, "The administrator [of EPA] shall approve the program if the proposed credits reflect good faith estimates by the State and the revision is otherwise in compliance with such Act [Clean Air Act]." This act also removed one of the more contentious aspects of the EPA I/M guidelines, called the "50 percent discount," which essentially established EPA’s preferred program as a sort of gold standard, and gave any proposed alternative program only half as much credit for producing reduced emissions, though EPA had not demonstrated any solid empirical basis for such an assumption.

Because of these revisions, California was able to enact a hybrid I/M program that incorporates a number of positive features, testing only 15 percent of the California vehicle fleet annually at test-only stations, while the remaining 85 percent can be tested at either centralized test-only facilities or decentralized test-and-repair facilities.

But additional reforms are necessary. Rather than relying on EPA’s continued flexibility to permit innovative programs such as California’s, the detailed requirements for enhanced I/M—Section 182 [c] [3] of the Clean Air Act—should be amended to allow nonattainment areas to use whatever methods they believe will best produce attainment with federal clean air standards while meeting the other concerns of their locality. These reforms are essential if alternative emission-control strategies are to be pursued quickly, while minimizing waste of societal resources. The current system of auto-emission control is flawed by perverse incentives, and those flaws center around I/M. Currently, EPA decides what programs are adequate to meet provisions of the 1990 Clean Air Act Amendments.

If EPA is unwilling to use its own authority to facilitate the implementation of an optimized auto-emission control system, policymakers might consider amending sections 172 [b] [2], 182 [a] [2] and 182 [c] [3] of the Clean Air Act in order to give states the power to determine what role, if any, I/M programs with scheduled testing of all vehicles have in an optimized clean-air plan for their own state’s noncompliance areas. 

F. Look Beyond the I/M Paradigm

While much can be done to render I/M an effective component of an optimized auto emission-control program, inspection and maintenance programs should not and need not dominate the other vital components of a comprehensive emission-control regimen. Like good health care, good auto care would involve much more than what we have now: a system of infrequent and easily falsified checkups with a few transportation control measures of dubious merit thrown in for good measure.

Over the long haul, the incentive structure for both motorists and vehicle-repair facilities needs significant revision, introducing real-time performance assessment, personal responsibility for keeping vehicles clean, and incentives to operate vehicles in an environmentally responsible manner. The best incentives would be those which reward continual maintenance of auto-emission control systems, penalizing motorists who drive vehicles with dysfunctional emission-control systems (and test facilities that facilitate such behavior), and providing incentives for driving the cleanest vehicle that people can afford to drive.

While an improved I/M program can address some of these issues, particularly using a clean-screen / extreme-emitter focus, the incentive issue could be addressed at an even more direct level, through a system primarily based on remote sensors or on-board diagnostic systems linked to an automobile emission-fee regime. That is, each vehicle would fall into a given emission class, based upon manufacturer’s data for that vehicle’s make and model year, as validated by remote-sensing or other readings. Motorists might pay these emission fees in a number of ways, including, for example, fees based on miles-traveled, or at-the-pump direct emission charges. Properly maintained cleaner gasoline vehicles and vehicles using cleaner fuels would pay considerably lower emission fees than older, conventional-gasoline, higher-emitting vehicles. 

Motorists detected as high polluters by a remote sensor might be reclassified as an "uncontrolled vehicle" and would receive a notification of projected registration fees for the following year based upon that category. Repair of the vehicle would allow for reclassification into its normal category with no penalty for the motorist, if repairs are done within, say, 60 days of the notification.

An emission-charge system would not only be efficient and effective, as we have seen from a myriad of other pricing systems, it would be a step toward greater fairness as drivers are eventually required to pay for the impacts they produce in closer and closer proportion to the scale of those impacts. It addresses a question that I/M cannot, such as the trade-off between owning an older, higher emission vehicle that one drives sparingly, versus owning a newer, much cleaner vehicle that one drives constantly. Such a system could also automatically evolve as emission profiles fed into the pricing system reflect the way that emission-control systems age over time.

But there are other aspects to driving in an environmentally responsible manner than the simple question of minimizing emissions. In the near term, even driving clean vehicles might not be enough to reduce air emissions to target levels. Clean vehicles today are very clean, but they still produce emissions, and a certain percentage of vehicles have broken emission-control systems and high emissions. Under conditions of extreme traffic congestion, these emissions can produce air-quality impacts at local and regional levels which result in unhealthful air quality.

As much research and experience has indicated, traffic congestion can be reduced in an efficient and equitable manner using appropriate variants of congestion pricing, in which time-varied roadway tolls are used to reduce demand for peak-period access to crowded facilities. In a landmark study performed for the California Air Resources Board’s Statewide Working Group on Market-based Transportation Control Measures, the authors studied the potential impact of a range of pricing structures for California’s urban roadway system. Table 6 shows the predicted reduction in vehicle miles traveled, vehicle trips, travel time, fuel consumption, air emissions and predicted revenue flows resulting from the imposition of an average congestion fee of $0.15 per mile for Los Angeles, San Diego, Sacramento, and San Francisco as based on expected roadway usage in the year 2010.