STATE COLLEGE — Every day, mechanics around the commonwealth check gas caps and look under hoods as part of annual vehicle emissions inspections.

But one state lawmaker says residents should no longer have to take their cars in for — and pay for — the annual inspections.

State Sen. John Wozniak, D-Westmont, said he thinks cleaner cars have made the inspections obsolete.

“I think the test needs to be tested,” said Wozniak, who introduced a resolution earlier this year asking the federal government to end the requirement. “Virtually all cars pass the test, and it’s time to re-evaluate whether it’s just a waste of money for consumers.”

The Pennsylvania Department of Transportation says about 4 percent of vehicles in the state annually failed the test in the past five years. In 2010, 4.22 percent of vehicles failed, and if one excludes the cases in which gas caps that failed were replaced, resulting in the car passing, the failure rate was only 2.43 percent.

However, state environmental officials say despite that, the inspections still play an important role in keeping the air clean.

“Motor vehicles are responsible for as much as half of the emissions causing ozone pollution in the commonwealth,” said Chris Trostle of the state Department of Environmental Protection’s division of air resource management.

Trostle said the federally mandated plan began in 1984 in Pennsylvania, starting with Philadelphia, Pittsburgh and the Lehigh Valley and now including more than two dozen counties.