Environmental Progress - Autumn 1996

New Tests, Technologies Promise Continuing Air Quality Benefits

Enhanced vehicle emissions tests are just around the corner for drivers in Chicago and Metro-East St. Louis areas

New tests using new technology will be added to the Illinois EPA's vehicle emissions test program in coming months, promising greater clean air benefits for residents of the Chicago and Metro-East St. Louis areas while continuing to keep the mandatory tests fast and convenient for motorists.

The first phase of one enhancement got underway in July 1996, but will not be noticeable to motorists since it involves identifying auto makes and models as they pass through the test lane, as part of preliminary research on gas cap effectiveness. The gas cap is the primary source of emission leaks from auto fuel systems. Functioning properly, it is designed to be a closed loop sending harmful vapors back into the system for recirculation.

By January 1997, the Illinois EPA hopes to have gas cap pressure test equipment ready for use. Once the program is running, a vehicle cannot pass the emissions test if it fails the gas cap portion, but will be eligible for re-testing as soon as a properly working gas cap is in place.

New IM 240 testing procedure ready to begin in 1997

During 1997, the Agency also plans to begin the IM 240 test procedure, replacing the current single speed idle test with a procedure utilizing a treadmill-like device to simulate actual operating conditions at various speeds. As the car operates on the device, called a dynamometer, vehicle exhaust will be captured and its emissions content measured and identified at varying acceleration and deceleration points.

Cars will continue to be tested every other year, starting when the car is two model-years old (for example, a 1996 vehicle will be tested in 1998, 2000, etc.) Model year 1981 and newer passenger cars and light duty trucks will be tested with the new procedures, since most cars manufactured after 1981 have the required computer components necessary to run the new test equipment. Passenger cars and light duty trucks from model years 1968 through 1980, and heavy duty vehicles from model year 1968 and newer will continue to be tested utilizing the current single speed idle test.

Since the new testing equipment will be very accurate in identifying vehicles that emit more pollutants than allowed, more vehicles may fail the test, but most properly maintained vehicles are still expected to pass.

With the new testing, as now, owners must take vehicles to a qualified repair technician for adjustment after a vehicle fails the test. Average repair costs have been estimated by the Illinois EPA at about $150. If a vehicle continues to fail the test after being repaired, the vehicle may qualify for a waiver.

In addition to being more comprehensive, testing will also apply to more vehicles in both the Chicago and Metro-East St.Louis areas when the new procedures begin. As required under the 1990 Clean Air Act Amendments, an additional 250,000 vehicles in the Chicago area and an additional 200,000 vehicles in the Metro-East area will be subject to testing, for a total of 5.1 million vehicles (4.75 million in Chicago and 350,000 in the Metro-East area).