This is one of the few good…

This is one of the few good moves the government has made - targeting the biggest polluters. And, because most cars that are old, have been manufactured under more recent pollution control guidelines (that is they were made after 2000) they pass or come close to passing. Drive Clean was needed when it was created but is no longer needed for passenger cars.

However, you need to make provision to fine people who modify more modern vehicles by replacing mufflers and catalytic converters with substandard or non functioning parts. Modified vehicles that spew pollution from the pipes need to be stopped.
Drive clean won't get at these vehicles but they need to be addressed.