Performance: Integrated Transport and Health Impacts Model (ITHIM) in the SF Bay Area

What it does: 

Integrated Transport and Health Impacts Model (ITHIM) forecasts the health impact of travel behavior and of interventions. This Microsoft Excel spreadsheet model can be used as a stand-alone model or combined with other transport and health models. In a 2009 London study, ITHIM revealed groundbreaking results showing that increasing active transport to reduce air pollution improves health outcomes significantly.


In 2011, the California Department of Public Health (CDPH) applied ITHIM to San Francisco (SF) Bay Area data to quantify health outcomes of transportation strategies to reduce greenhouse gas emissions. CDPH looked at four potential scenarios in the SF Bay Area and focused on the health outcomes associated with increased active transport and reduced carbon levels emitted from cars.

Cost & Financing: 

CDPH conducted this study with the financial support of foundation and public health sources. As of June 2014, the model is available free of cost to users, although users need extensive training to implement it properly.


ITHIM revealed that an increase in active transport from 4.5 to 22 minutes/day would result in major reductions in chronic diseases: 14% decrease in heart disease, stroke, and diabetes; 6-7% decrease in dementia and depression; 5% decrease in breast and colon cancer. The study also showed that even though there would be a significant 19% increase in injuries to pedestrians and bicyclists, the SF Bay Area would still experience 2,300 fewer deaths and more than 23,000 years of life would be gained.
ITHIM estimates that if active transport increased to 22 minutes/day, the SF Bay Area would save $1.4-$21.8 billion annually from health cost savings, extend average life expectancy by 9.5 months, and reduce CO2 emissions 9% to 15% from the 2000 baseline.

Key Contacts: 

Name Organization Phone Number E-mail
Neil Maizlish CDPH (510) 620-3128
Sean Co MTC (510) 817-5748
James Woodcock

Centre for Diet and Activity Research, University of Cambridge

01223 746887

This study is the collaborative effort of the California Department of Public Health, the developers of ITHIM, the Metropolitan Transportation Commission (MTC), and the Bay Area Air Quality Management District. James Woodcock led the development of ITHIM.

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Last Updated August 19, 2014 | Written By Mimi Tam

About This Library

The Best Practices Library provides numerous examples of ways to address health and equity in regional transportation decisions.