California Extreme Heat Adaptation Final Guidance Document – Transportation Recommendations

California’s Climate Action Team (CAT) developed the guidance document, Preparing California for Extreme Heat: Guidance and Recommendations, to provide California agencies with best practices for adapting to heat-related climate change impacts. Several of the recommendations focus on adaptations to the transportation sector and make recommendations for actions that can be taken by the California Department of Transportation (Caltrans) to increase heat resilience. Transportation improvements, such as road pavement and the removal of vegetation, can contribute to higher temperatures in urban areas resulting in what are often referred to as urban heat islands. The transportation-related recommendations focus on mitigating urban heat islands and will be the focus of this case study.

The Guidance recommends that Caltrans develop standard specifications for cool, porous, or sustainable pavements and examine opportunities to expand the use of these materials to reduce local surface temperatures at state-owned and maintained parking lots, park and ride lots, and state highways. The guide notes that Caltrans’ use of these materials will provide a model for localities and the private sector to implement their own porous pavement programs to adapt to climate change. The Guidance also recommends that future updates to California’s Green Building Standards Code consider incorporating the standard specifications for cool or sustainable pavements developed by Caltrans.

Other recommendations include promoting the use of urban greening and green infrastructure to reduce heat in public and private spaces. Specifically, the Guidance recommends planting trees and other vegetation to create shade at both urban and open spaces, restoring urban streams, and educating the public on best practices in urban greening. In addition, the Guidance recommends development of an urban heat island effect index. The index will allow cities to set quantifiable heat reduction goals and measure results of heat reduction programs.

The Guidance also recommends increasing coordination between agencies, employers, and the media to convey necessary heat protection measures for at-risk workers, including transportation workers. Those with physical jobs, especially those who work outside, are more susceptible to heat related illnesses during extreme heat events. Because transportation workers work primarily outside, increased preparedness for extreme weather events is necessary to protect worker safety. The guide also recommends training employers and workers in worker protection measures, including recognizing heat risks and providing adequate water, shade, and rest breaks.

To facilitate the adoption of a formal adaptation plan, the Guidance lists areas for further research. With respect to transportation, the Guidance recommends that Caltrans research the life-cycle costs and benefits of lighter colored (i.e., higher albedo) pavements.

The Heat Adaptation Workgroup that developed this Guidance is a subcommittee of the Climate Action Team Public Health Workgroup. The Climate Action Team coordinates California climate policy, and is made up of nine working groups, each focusing on a different area of the state’s economy and resources. The workgroup is co-chaired by the California Department of Public Health and the California Environmental Protection Agency and includes staff members from other State agencies, including the California Air Resources Board, California Department of Forestry and Fire Production, and the California Department of Transportation (Caltrans). The agencies collaboratively developed the recommendations in the guidance.

The Workgroup worked with scientists from the California Energy Commission’s Public Interest Energy Research Group. Climate model data was obtained from the Scripps Institute of Oceanography, University of California San Diego. Climate models for California consistently project an annual average temperature increase of up to five degrees by 2030 and up to ten degrees by 2100. The Guidance was prepared with an understanding that, as average annual temperatures rise and extreme heat events become more common, increased economic, ecological, physical, and social harms will occur and agencies should consider this information in their planning -- including transportation planning. The Guidance provides detailed information on the impacts of extreme heat on public health and safety with the goal of helping in the development of policies that reduce the possibility of heat-related deaths in vulnerable populations due to extreme heat events. While the recommendations in this Guidance focus on state agency actions, these recommendations may also be useful for local and regional entities as they develop climate change plans to prepare for longer, hotter, and more frequent extreme-heat events.


This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on December 29, 2014.

Publication Date: October 2013

Author or Affiliated User:

Related Organizations:


Resource Category:

Resource Types:

  • Best practice
  • Policy analysis/recommendations

States Affected:


Go To Resource