SACRAMENTO - The State Air Resources Board (ARB) is expected to establish the state's first roadside emissions tests for diesel big-rig trucks, buses and other similar vehicles during a public hearing Thursday.

The tests, which will be similar to the "Smog Checks" for passenger cars, will be conducted at weigh stations and other roadside locations by roving teams of inspectors and is aimed at reducing excessive soot-like particulate emissions, often caused by tampering or neglected maintenance.

The tests are an addition to other anti-soot standards already adopted by the ARB, including tighter tailpipe emission limits that will make 1991 buses and 1994 trucks "smokeless" and standards for the clean-up of diesel fuel, scheduled to go into effect in 1993.

The hearing will begin approximately 10 a.m. (at the conclusion of an earlier, unrelated hearing) in the auditorium of Lincoln Plaza, 400 P St., Sacramento.

 Photo opportunities include trucks on display on the west side of the building that will show the difference between excessive smoke and a truck that meets the proposed roadside standards. They will be available for demonstration after 8:30 a.m. and throughout the hearing.