On the eve of the state S1nog Check programs' first anniversary, the Air Resources Board will be conducting roadside tests of about 2,000 cars in major urban areas over the next four months to study how well the program is working and the extent of tampering with anti-smog devices. 

The roadside inspections, with help from the California Highway Patrol and state Bureau of Automotive Repair will help researchers understand how often and how well cars are maintained by their owners and the extent to which anti-smog systems are tampered with or leaded gasoline is illegally used in newer catalytic converter-equipped cars. 

The tests will begin a three-week run in the Los Angeles area beginning March 11 and will be conducted in Ventura, San Diego, Sacramento, San Francisco and Fresno through June. 

ARB Chairman Gordon Duffy emphasized that the tests, which can be done in about 20 minutes, are purely tor research anu that no citations will be issued a ticket for illegal engine modifications. He also explained that the tests may provide clues about the effectiveness of the state's Smog check program, which began once-every-two-year inspections of automotive anti-smog systems last March. 

"Since the program is now a year old, about half of all cars in the state's urban areas have gone through the inspections, "Duffy explained. "These roadside tests may tell us whether cars that have already gone through the Smog Check comply with the state's anti-smog laws better than cars that will be tested in the next year." 

"These tests also are part of our ongoing research program to study the durability of anti-smog systems ana the mainte11ance habits of California car owners," Duffy said.  "Cars participating in the tests will be selected at random and directed to inspection lanes set up on the side of major streets."

The test will include an under-the-hood inspection of anti-smog controls and tailpipe readings of pollutants at idle and at 2500 rprn. 1975 and 11ewer cars, which are factory-equipped with catalytic converters, will have fuel samples taken and a tailpipe test to determine if they have been illegally fueled with leaded gasoline. Motorists flagged down for the test will be given a check list showing the condition of their car's pollution control system.

Duffy said the check list "could provide car owners with clues to poor arivir1g performance or low gas mileage caused by faulty maintenance or tampering with anti-smog controls." 

"Motorists who tamper with anti-smog systems, in the mistaken belief they can improve a car's performance, actually cause the very problems they think they're trying to solve. Duffy said. "Especially on newer cars, which are run by computers that constantly tune the car while it's being driven." 

Preliminary results of the state's Smog Check program, which has tested about 3.5 million cars since last March, show that about one-third of all cars fail the test. Emissions of smog-forming hydrocarbon and carbon monoxide, however, are reduced by about 50 percent with low-cost repairs or adjustments. 
Random roadside tests conducted by the Air Resources Board in 1983 showed about 68 percent or the cars complying with anti-smog laws. Eighteen percent of cars tested in 1983 were found to have one or more of the smog control systems not working properly and another 14 percent showed signs of tampering or illegal removal of emissions control equipment.