Colorado’s Transportation Planning Rule to Reduce the Greenhouse Gas Pollution Impacts of Planning Choices in the Built Environment

For many years, the question of how to measure the pollution impacts of infrastructure choices in the built environment has perplexed policymakers, complicated by the reality that use of any transportation system affects the choices of countless individuals in their daily lives. Nonetheless, extensive research as well as common sense reflect that the options available—and the infrastructure built primarily by public sector agencies—influence the choices that those individual users are able to make. With transportation being the number one source of greenhouse gas pollution in the U.S.A., the implementation of practical approaches to tackling this urgent problem depends on establishing viable policies and methodologies for assessing and regulating these impacts of building choices, often referred to as “induced demand.” Colorado’s recently implemented Greenhouse Gas Pollution Reduction Planning rule, established in 2021 following new state legislation, offers a case study of a system to implement pollution reduction targets for transportation planning agencies, leveraging the competencies, authorities, and influences of specific institutions that govern transportation planning within the state.