By a 25-21 vote, the Senate approved the optional dynamometer plan. Both Sen. Donald F. Munson, R-Washington, and Sen. John W. Derr, R-Frederick/Washington, voted in favor of the voluntary plan.
Although it stopped short of what some consider the ultimate goal - dumping the program entirely - the bill does send a message, Munson said.
"We're making a statement to the federal government that we're not going to let them shove this down out throats," he said.
The mandatory tailpipe test, which went into effect in Washington County last year, tests emissions from an idling vehicle. On the dynamometer, the car's engine runs at highway speeds on a treadmill while sensors measure the car's output of hydrocarbons, carbon monoxide and nitrogen oxide.
Many experts consider the dynamometer test more accurate, but motorists have voiced displeasure with the test. A chief complaint is that the test is intrusive because testing center attendants - not vehicle owners - drive the car on the treadmill.
"I think the vast majority of my constituents resent the whole program," Munson said.
Washington County has one of the highest rates of people opting to take the dynamometer in the state, but many residents have questioned why the county has to be subjected to the same pollution restrictions as the more-polluted metropolitan areas.
"Basically I don't see a need for it and don't want it," said Robert A. McKee, R-Washington.
McKee said he would like the program to be eliminated, but having the dynamometer optional is better than nothing.
Several lawmakers have received letters from the Environmental Protection Agency warning of possible sanctions without the stricter emissions program. Penalties could range from losing nearly $100 million in federal highway funds to having the EPA take over the state's clear air program.
"Essentially, they're saying they're not going to grant any exceptions. Case closed," Poole said.