TRB’s Airport Cooperative Research Program (ACRP) Web-Only Document 11: A Comprehensive Development Plan for a Multimodal Noise and Emissions Model explores development of a tool that would allow for the assessment of the noise and air quality impacts on the population from multiple transportation sources, assess the total costs and impacts, and assist in the design and implementation of mitigation strategies. The availability of a multimodal noise and emissions model could help inform airport and policymakers charged with evaluating and making decisions on expanding transportation facilities.