What type of vehicle modification requires prior approval from the Pennsylvania Department of Environmental Protection?

Modifications that impact emissions controls are subject to prior approval from the Pennsylvania Department of Environmental Protection to ensure compliance with state and federal emissions regulations. These regulations are designed to protect air quality and public health by minimizing harmful vehicle emissions. Any changes that could affect how a vehicle manages its emissions system, such as alterations to the exhaust, the addition or removal of catalytic converters, or modifications to the engine management system, must be evaluated to ensure they do not lead to increased emissions or violate environmental standards.

In contrast, modifications such as changes to the audio system, cosmetic alterations like custom paint jobs, or upgrades to tires typically do not have a direct impact on emissions controls and are therefore generally not subject to the same regulatory scrutiny. These types of changes are more related to vehicle aesthetics or performance but do not affect the vehicle's emissions output or compliance status.