Project at a Glance

Title: Open Source Integrated Transport and Health Impacts Model (ITHIM)

Principal Investigator / Author(s): Maizlish, Neil

Contractor: UC Davis

Contract Number: 17RD025

Research Program Area: Health & Exposure

Topic Areas: Health Effects of Air Pollution, Transport


Every year, more than 30,000 Californians die prematurely from traffic injuries and chronic diseases linked to physical inactivity and air pollution. The transportation system in California impacts our health in both positive and negative ways. It enables us to access goods and services, jobs, and opportunities, however, car-centric transportation is associated with long and sedentary commuting, noise, air pollution, urban sprawl, community severance, and traffic injuries. Active travel for transportation can improve public health by offering opportunities for physical activity through walking and cycling and decrease the production of air pollution. Low levels of physical activity contribute to the premature deaths of Californians each year and raise the risks and costs of major chronic diseases. According to the California Household Survey and the US Behavioral Risk Factor Survey, about 20% of Californians indicate low to no physical activity.The transportation sector also accounts for about 40% of directly emitted greenhouse gases annually in California. These gases lead to warming air temperatures, which favor the formation of health harming smog. Replacing short trips taken by cars with walking, cycling, and transit represents a double win: improving health and reducing greenhouse gas emissions. ITHIM which stands for Integrated Transport and Health Impacts Model (ITHIM) is a tool that can calculate the health benefits, harms, and cost savings of active transportation. The California version of the ITHIM planning tool answers the question of "How much health benefit we can expect by changing our mode of transportation from cars to active transportation such as walking and biking?" The ITHIM tool calculates the change in fine particulate air pollution from vehicle exhaust, physical activity from walking and cycling, and injuries from traffic collisions that result from a change in transportation from vehicles to walking and biking to assess the overall benefit in health as well as the costs from changes in air pollution, physical activity, and traffic injuries.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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