New Auto Emissions Test Goes up in Smoke

Published April 1, 1999

The Environmental Protection Agency’s new auto emissions test literally went up in smoke at its formal Chicago media introduction February 1.

The test, known as IM 240, places a vehicle’s drive wheels on a dynamometer to simulate a range of driving speeds up to 57 miles per hour. Though originally designed to be conducted in laboratories by highly trained technicians, the dynamometer emissions tests are being conducted in the field by $6.50- to $7.00-per-hour workers employed by Envirotest, under contract to the Illinois EPA.

Among those attending the IM 240’s media introduction in Chicago was Robert Brooks of Ward’s Engine and Vehicle Update, [an authoritative source in the field . . .] As the first car put on the dynamometer picked up speed, Brooks reported, a front tire began squealing loudly. The air was filled with the smell of burning rubber and smoke could be seen coming from the tire. “The testing was not stopped promptly,” reported Brooks, “and apparently no effort was made to warn the vehicle owner that a tire had been damaged, thereby increasing the potential for a safety hazard, particularly at freeway conditions.”

Brooks’ report was confirmed by Gail Fischer of CLTV, the Oak Brook, Illinois-based cable news network, who also witnessed the test.

Illinois EPA Denies Incident; Admits Problems

While an Illinois EPA Vehicle Emissions spokesperson told Environment News she had not been informed of the incident, she did acknowledge being “aware of a few tire problems in the first two weeks of the program.” She declined to address the specific nature and cause of the problems or their frequency, referring us to Envirotest.

Traveling in Vancouver, British Columbia, Envirotest spokesperson Laura Baker called to flatly deny there had been any problem at the February 1 event–no squealing tire, no smell of burning rubber, no smoke. She acknowledged that, although present at the February 1 event, she had not remained in the test lanes the entire time. Baker noted that Envirotest had tested 152,000 vehicles in the first two weeks of the new program, and only 16 damage claims had been filed.

Experts Express Concern

“Somebody really screwed up,” a tire engineer told Environment News when we discussed the event with him. Requesting anonymity, engineers at both Goodyear and Firestone/Bridgestone confirmed that, while a complex set of factors determines a tire’s fate in the dynamometer test, there is no question that the small-diameter double-roller dynamometer employed in the IM 240 test is harder on tires than normal driving.

While the engineers emphasized that catastrophic tire failure is unlikely to result from the test, one engineer said that ply separation, causing sudden “thumping” and a flat tire, is possible if the test severely damages a tire. The likelihood of severe damage depends on several factors, including the degree to which the tire is under-inflated and its age and condition, as well as improper dynamometer load settings.

James Halderman, professor of automotive technology at Sinclair Community College in Dayton, Ohio, told both Brooks and Environment News that tires inflated more than 8 PSI below the recommended pressure could be subject to damage.

Motorists preparing for an IM 240 emissions test would do well to check tire pressure, as Envirotest technicians do not do so. According to Envirotest spokesperson Baker, the company’s technicians only visually inspect the tires–a highly unreliable indication of tire pressure according to all tire experts contacted for this story by Environment News.

Other Serious Problems Plague the Test

Both Ward’s Engine and Vehicle Technology Update and the Chicago Tribune have reported instances of the wrong wheels being put on the dynamometer.

The front wheels of a rear-wheel drive Cadillac were put on the dynamometer at the February 1 event. When the car was put in gear and the engine accelerated, it attempted to jump out of the chocks holding the drive wheels, according to another journalist who was present. The Tribune, which sent its reporters to other test stations rather than attend the staged event, reported another Cadillac put on the dynamometer incorrectly. The paper reported, “when the worker (test driver) hit the gas the car lurched forward, nearly driving out of the safety blocks. Several times, the driver hit the gas, rocking the car forward and backward.

“Other workers gathered around and looked under the car, eventually concluding that the problem must be that the car’s parking brake was malfunctioning. Most mechanically-inclined teenagers, looking under the car, probably would have noticed the drive shaft and rear differential characteristic of a front-engine, rear-wheel drive vehicle. When informed that it was the back wheels that made this car go, they repositioned it.”

Little or No Impact on Air Quality

While concern mounts over the safety of EPA’s new test, there remains serious doubt as to whether it is of any value in improving air quality.

In a well-documented report for the Fraser Institute in Vancouver, British Columbia, Paul Connix writes:

“Virtually all the U.S. EPA research on I/M programs found in the technical reviews is of such poor quality that it is unlikely that a reputable scientific journal would consider any of them for publication. It is difficult to imagine how any government official who has taken the trouble to read the technical reviews–rather than skimming over the abstracts–could be convinced of the value of I/M programs as an effective strategy for the reduction of emissions.

“In the early 1990s,” Connix continues, “research on I/M programs from sources other than the U.S. EPA began to be published. These articles showed that existing I/M programs provided little or no environmental benefit (see, for example Lawson et al. 1990, 1993). In 1991, the U.S. EPA’s entire strategy of ozone reduction was questioned in a 500-page book published by the U.S. National Research Council (US NRC 1991), and the U.S. General Accounting Office (GAO) began a series of reports that were highly critical of the quality of science done by the U.S. EPA, and of the computer models that the U.S. EPA used to predict the effectiveness of its I/M programs (e.g. US GAO 1992,1994,1997).

“In fact, only in January of this year was a study of vehicle emissions programs launched by the National Academy of Science, after funds for the work had been held up for 15 months.”