The EPA states that noise from engines, intake, exhaust and tires make up the primary sources of motor vehicle noise. However, the previous inspection regimen focused heavily on restricting noise from engines, intakes, and exhaust. With advancements in automotive technology, sources of noise from city driving are not limited to the power systems of vehicles; tire noise has seen a steady increase in relative importance. Newly promulgated UN and EU noise control limits and inspection methods have drastically changed the tests for noise produced by vehicle acceleration.

To effectively reduce the impact of city traffic noise on people’s lives, the EPA referred to new international regulations to draft the latest amendments. Specifically, the EPA based the revisions on the EU’s new vehicle noise standards (UN/ECE R51.03), which were promulgated in February 2016 and went into effect in July 2016.

The EPA noted that the amendments are consistent with international standards for regulating noise due to acceleration. They also take Taiwan’s population density into consideration, based on comprehensive evaluations of traffic noise in Taiwan. The amendments particularly tighten controls for rear engines standards when stationary, which is set at a standard value of two decibels. This will be done in order to further improve motor vehicle noise control.