Presentations and discussions at the three exchanges demonstrated that political, regulatory, geographic, and economic context significantly affect how a region or Sstate approaches climate change mitigation. Some of the most salient factors and their impacts on mitigation are outlined below.
Uncertainty regarding Federal transportation and climate policy leaves States and regions unsure of how to proceed.The three peer exchanges took place before the passage of the surface transportation reauthorization, 'Moving Ahead for Progress in the 21st Century Act' (MAP-21), and peer exchange participants expressed concerns about uncertainties regarding reauthorization and requirements related to transportation programs, greenhouse gas analysis, and climate change strategies. Similarly, participants expressed concerns that Federal action on climate change - whether through national legislation or regulatory action - such as possible cap-and-trade legislation, vehicle carbon dioxide emissions standards, or other policies, could change their preferred strategies.
Attainment status under the Clean Air Act affects existing modeling capabilities and funding availability for emissions reduction strategies.Regions in nonattainment or maintenance status of the National Ambient Air Quality Standards (NAAQS) for criteria pollutants (carbon monoxide, nitrous oxides, ozone, and particulate matter) have experience with conducting regional emissions analysis for conformity. As a result, they are generally better prepared to perform emissions analysis related to GHG emissions, since they often have staff dedicated to this analysis and experience with emissions modeling. Meanwhile, States and MPOs without air quality issues often find it challenging to address GHG emissions. For example, while Vermont has political support for reducing GHG emissions, it has been in attainment for many years and has less of the expertise required to analyze its GHG emissions and strategies. Similarly, areas such as the Miami region, which are in attainment of Federal air quality standards and do not receive Federal money from the Congestion Mitigation and Air Quality Improvement (CMAQ) Program do not have a dedicated source of funding for emissions reduction projects. While CMAQ helps to fund programs that reduce emissions of criteria air pollutants, these programs typically also reduce GHGs.
Level of public interest and belief in climate change affects what is feasible and how it is described and marketed.The degree to which climate change is viewed as a threat and as an appropriate policy priority varies across the country. Some areas recognize it as a critical issue and support MPO or DOT activity to reduce transportation energy intensity, while others are dominated by vocal opponents who do not believe that climate change is occurring or do not believe that it is caused by human activity. Other areas may recognize climate change as a concern, but place a higher emphasis on economic growth or other issues. It is important for transportation agencies to understand the political context related to climate change, and to develop strategies and communicate about them in ways that emphasize benefits of interest to the public and decisionmakers, such as positive economic impacts, saving money, or improving regional air quality.
Population growth affects emissions reduction potential.Many of the metropolitan regions represented at the exchanges are growing rapidly, including Atlanta, Houston, San Diego, and Los Angeles. On the one hand, increasing development, if managed well, can help to make transit more viable and support transit-oriented development, which reduces per capita emissions. On the other hand, an increasing population will typically increase total emissions and can expand the metro area's GHG footprint. A lesson is that it is important to account for population growth if establishing GHG reduction targets, and to use appropriate metrics for communicating the benefits of long-range transportation plan alternatives.
Presence of manufacturing or ports can generate significant freight emissions, which are challenging for States and MPOs to address.While many transportation mitigation strategies focus on passenger travel, freight is a major contributor to GHG emissions that typically falls outside of measures that DOTs and MPOs control, and some participants felt that freight emissions are more appropriately addressed at the national level. Freight traffic is determined by the presence of freight facilities and national or even global economic forces. Furthermore, ports along each coast compete against one another and so are not inclined to take actions that might reduce their competitiveness. Areas with ports or truck freight terminals must accommodate a large amount of truck traffic and idling as trucks wait to load or unload, as materials are transported from trucks to ships, and while ships sit in the harbor. While this activity is positive for the region and Nnation's economy, States and regions are often challenged in taking actions to reduce freight GHG emissions. Freight-related travel and emissions are also more difficult to predict.