Dillon Valley I-70 noise wall

The National Environmental Policy Act (NEPA) requires federal agencies, in cooperation with state and local governments, to address the environmental impacts of a proposed federal action or an action that receives federal funds. CDOT must comply with NEPA and the environmental procedures established by the Federal Highway Administration (FHWA).

Traffic noise is an important consideration that must be taken into account when CDOT embarks on environmental studies that involve major highway improvements. For these projects, a noise study is required to assess existing noise levels and predict future noise levels (usually 20 years into the future) to determine noise impacts.

All traffic noise analyses prepared for CDOT projects must adhere to procedures and requirements as established by federal law, U.S. Department of Transportation regulations and CDOT noise guidelines. This ensures that the policies are uniformly and consistently applied and provides equitable treatment for those impacted by highway traffic noise.