The Congestion Mitigation and Air Quality Improvement (CMAQ) program was enacted as part of the surface transportation legislation. This work recommends that Congress retain the sole federal surface transportation program that funds projects to reduce pollution and traffic congestion in areas that must comply with national air quality standards.

In 1994, the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA), in cooperation with the Environmental Protection Agency (EPA) conducted a 10-State review of the Congestion Mitigation and Air Quality Improvement (CMAQ) Program. The CMAQ Program was created in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) and this mid-term review assessed the first 3 years of program activities. This mandated review was intended to determine whether current projects and policies support the goals of the program.

In reviewing proposals for transportation research programs as part of reauthorizing the federal surface transportation program, the Transportation Research Board recognized a gap: no proposals explicitly addressed research to mitigate GHG emissions and energy consumption attributable to passenger and freight travel or to adapt to climate change. A Transportation Research Program for Mitigating and Adapting to Climate Change and Conserving Energy is the product of a study to suggest research programs to fill this and other perceived gaps. Specifically, this book identifies research needs with regard to policies and strategies relating to the use of the transportation system and to assist infrastructure owners in adapting to climate change; focuses on research programs that could provide guidance to officials at all levels responsible for policies that affect the use of surface transportation infrastructure and its operation, maintenance, and construction; and aims to help officials begin to adapt the infrastructure to climate changes that are already occurring or that are expected to occur in the next several decades.