Vehicle inspection and maintenance program U

Motor vehicle I/M programs have been considered to be cost-effective in the U.S.

and are required by the Clean Air Act Amendments of 1990 in regions with the most

challenging air pollution problems (Eisinger, 2005). The Transportation Research Board

analyzed 20 mobile source control measures and found that I/M was the most

cost-effective, averaging $2000/t of pollution lessened, a value considered good in the air

quality management field (Transportation Research Board, 2002). The main purpose of

I/M programs is to encourage better maintenance for in-use vehicles and to assure the

vehicle emission control systems are functioning properly through periodic inspection.

The rationale for an I/M program is that the emission distribution among the vehicle

population is highly skewed: a small portion of vehicles (estimated at 5-10%), sometimes

called gross polluter vehicles, is responsible for a substantial fraction (variously estimated

at 50 to 80%) of total vehicle emissions (Harrington, 1997; Beaton et al, 1995). Moreover,

not only old vehicles can be gross polluters, but also vehicles of all model years may

include some proportion of gross polluters (Beaton et al, 1995), due to the factor that

vehicle emission levels are heavily dependent on maintenance. This problem can be even

more highlighted in developing countries, where vehicles have a long lifetime and are

often poorly maintained (Sterner, 2003). In this case, upgrading maintenance practices

and replacing the worst engines should be considered first before moving on to better

technology (World Bank, 2001). In addition, despite technological and regulatory

advances, new vehicle standards are not sufficient to achieve pollution abatement goals if

vehicles deteriorate rapidly, resulting in increasing emission rates (Sterner, 2003).

Therefore, to control rapidly growing vehicle emissions, governments must not only

affect the behavior of vehicle manufacturers and fuel suppliers, but also the actions of

drivers in terms of how well they maintain their vehicles regardless of their vehicle ages

(PA Government Services, Inc, 2004). However, although simple in concept, the detailed

design and implementation of I/M programs is challenging. For example, when emission

control equipment malfunctions, vehicle performance may be unaffected, hence the driver

has no private incentive to seek repairs, and demanding private expenditures of money

evade the regulation in numerous ways (PA Government Services, Inc. 2004). The

practices of I/M programs in the U.S. have shown various barriers that may cause failure

of these programs to generate the emission reduction originally anticipated by policy

makers. For instance, motorists may have many opportunities to evade required repairs

such as testing vehicles numerous times until they happen to pass. By and large,

launching an effective I/M program requires massive behavior change among the drivers

of a region (PA Government Services, Inc. 2004)

Despite the remaining controversies, the I/M programs in the U.S., in particular

the enhanced I/M established by the U.S. EPA in 1992, have played an important role in

assisting states to achieve air quality standards. For example, in the state of California, the

enhanced I/M programs were responsible for about 25% of the emission reductions

required by 1999 under the State’s 1994 Ozone State Implementation Plan (California Air

Resource Board, 2000). In developing countries, the I/M programs in Mexico City,

developed with the assistance of the World Bank, are regarded as one of the most

successful cases. The case of Mexico City demonstrates that substantial and sustained

mobile source emissions reductions and air quality improvements are possible through

effective I/M programs that are characterized by committed leadership, the right

institutional design and the right incentives (PA Government Services, 2004). At present,

I/M programs are considered to be a core air pollution control measure in severely

polluted urban areas (Eisinger, 2005). Moreover, traditional I/M programs focus primarily

on gasoline-fueled vehicles. However, given the increasing public awareness of the health

and environmental threats posed by emissions from diesel-fueled vehicles, there is a

growing interest to introduce equivalent programs and test protocols also for diesel-fueled

these vehicles11. Testing equipment for PM emissions is less mature and more expensive

compared with those for CO, HC and NOx(main air pollutants in gasoline exhaust).

Currently, the most commonly used procedure is opacity testing, but its accuracy in terms

of measuring levels of PM emissions is facing a lot of challenges. Nevertheless, the

ongoing development in test procedures and technologies (e.g. new PM meters capable of

measuring PM vehicle emissions) makes PM-oriented I/M programs more attractive for

policy makers to consider.

In Bangkok, the existing I/M system was initiated in 1994, and applies to all six

provinces in the Bangkok Metropolitan Region (defined as the city of Bangkok and its

surrounding five provinces, details will be provided later), which is a hybrid vehicle

inspection system comprising government-operated centralized inspection stations and

privately operated inspection stations (Parsons, 2001). Parsons’ report states that

Bangkok’s existing I/M programs are ineffective at detecting vehicles that do not meet the

emission standards due to various reasons, including common use of dysfunctional test

equipment, non-consistent administration system, lack of skilled test workers,

non-automated facilities, poorly managed data records, and so forth, resulting in

continued excessive emissions. Another study by Pala-En (1998) also found that 17 of 30

(56.7%) selected private motorcycle inspection centers in Bangkok did not follow the

standard testing procedure of the Department of Land Transport to issue a certificate of

compliance and more than 60% of these inspection centers had technician practices scores

in low levels, which were in the range of 4.50-13.25 out of a total of 25 points.

Upgrading the existing I/M programs is needed to improve the effectiveness of the

programs. Furthermore, the main reason that makes an effective diesel-related I/M

program desirable in Bangkok is, as discussed before, that the principal sources of PM

11_{Source: Clean Air Initiative, Air quality information systems,}

pollution in this area are diesel-fueled vehicles (including most city buses, city trucks,

light duty trucks, vans, etc), in particular those old ones lacking emissions control, which

can contribute more than 50% of the total PM10 emissions. Given that pollution levels

from diesel vehicles are heavily dependent on maintenance, and a well-maintained diesel

vehicle will generally retain a good emissions performance throughout its operating life,

it is expected that in Bangkok considerable reductions in PM emissions from mobile

source will be delivered through effective I/M programs targeting related vehicles.

Parsons’ final report on the Bangkok Air Quality Management Project

recommends an effective I/M system targeting all diesel-fueled vehicles and motorcycles

to be the most cost-effective control measures to mitigate PM pollution in the BMR.

Overall, they estimate that I/M programs will cut current mobile source emissions by up

to 25%. However, a key gap in Parson’s report is that in estimating the emission reduction

benefits associated with the proposed I/M programs, they did not take into account the

uncertainty about the actual effects of the programs in reducing PM emissions. Instead,

they only considered the ideal case that all violating vehicles would be identified and

properly repaired. Based on the past experience in the U.S., the actual effectiveness of

I/M programs in reducing PM emissions can vary significantly, or be much lower than the

levels anticipated. For instance, five studies have estimated the reductions in light-duty

motor vehicle hydrocarbon exhaust emissions from California enhanced I/M vary in the

range of 12-34% (summarized by Eisinger, 2005). In theory, vehicular emission

reductions available from I/M programs are mainly determined by the failure thresholds,

or cut points, used to identify problem vehicles, but are also quite sensitive to a variety of

factors, such as the actual percentage of problem vehicles identified, the percentage of

problem vehicles waived from repairs or operating illegally, the emission reduction

Given the considerable uncertainty involved in the total emissions reductions

achieved by I/M programs, this study takes into account this issue and examines its effect

on the total benefits (health benefits are considered here) of the programs. Furthermore, in

order to understand how I/M program design considerations, i.e. the change in factors that

affect the total reductions in vehicle emissions achieved by an I/M program, would alter

the total health benefits of the program, an I/M program-evaluating tool developed by

Eisinger (2005) will be employed and linked to health benefit analysis12. This tool

incorporates a complete list of factors that affect the effectiveness of an I/M program and

allow the users to predict the total percentages of vehicle emission reductions achieved by

the program. The theoretical basis and modeling details of this tool is discussed in

Chapter 3.

In document Health benefits of traffic-related particulate matter control policies : the case of Bangkok, Thailand (Page 60-65)