Emissions testing laws are a crucial component in the fight against air pollution and climate change, yet these regulations vary significantly across the United States. Understanding these differences ...

The emission measurement procedure using the “free acceleration” method has caused many diesel vehicle owners to worry about engine impact.

Depending on where you live in the United States, emissions testing of old cars may or may not even be a thing. There are 28 states where at least some (though not necessarily all) are required to ...

Add Yahoo as a preferred source to see more of our stories on Google. If you're due to get your vehicle tested for pollutant emissions, the process is now a bit easier in the Milwaukee area: the state ...