A recent study by Berkeley epidemiologist Neil Maizlish found that “physical activity due to increased biking and walking would have a profound impact on health and economic outcomes while contributing to State GHG and VMT reduction goals.”
The California legislature in recent years has enacted policies designed to promote strategies to lower transportation-related greenhouse gas (GHG) emissions by reducing vehicle miles traveled (VMT).
Dr. Maizlish writes: “An important component of VMT reduction is promoting active transportation – walking and bicycling. Active transportation increases physical activity, which improves population health by reducing risks of heart disease, stroke, diabetes, dementia, depression, and some types of cancers. In 2010, more than 23,000 deaths could be attributed to physical inactivity in California.”
His research asked:
- How many deaths could be avoided and how many years of life could be gained if Californians: a) doubled their walking and transit trips and tripled their cycling, and b) further increased biking and walking to meet the U.S. Surgeon General recommendations for physical activity?
- What would the economic impact of improved public health due to increased physical activity be under these scenarios?
- What would the impact on GHG emissions be?
Dr. Maizlish, using data from California travel and health surveys, vital statistics, collision databases, and regional and statewide travel models, and the Integrated Transport and Health Impacts Model (ITHIM) created a model that “estimated the number of deaths and years of life lost, disability, economic, and greenhouse gas emission outcomes if the 2010 California population met ambitious mobility and health goals.”
He found that “California achieving its stated goals of doubling walking and transit trips and tripling bicycling by 2020 would annually eliminate 2,348 annual deaths from chronic diseases, but add
254 deaths from traffic collisions – overall leading to 2,095 fewer deaths and 30,124 fewer years of life lost and disability.
His findings include:
- In an optimum health scenario that increases active transport for a typical Californian to21.4 minutes per day – a level recommended by the U.S. Surgeon General–California could experience 8,057 fewer annual deaths and 142,101 fewer years of life lost and disability.
- The annual value of preventing premature deaths and disability ranged from $1 billion to $15.5 billion for the mobility scenario of doubling walking and transit trips and tripling bicycling, and $5.7 to $59.6 billion for the optimum health scenario, depending on the method of monetizing deaths and disability.
- Assuming half the increases in active transport are offset by less car travel, annual car carbon emissions would decline between 3% to 14% compared to the 2010 baseline over the range of scenarios.
California legislation and policy promote land use strategies that mitigate transportation-related greenhouse gas emissions by reducing vehicle miles traveled (VMT).
The research examines, for example, SB 743 that was passed in 2013. It “intended to balance the needs of congestion management with statewide goals to promote infill development, public health through active transportation, and reduction of GHG emissions.”
SB 743 created “incentives for compliance with the California Environmental Quality Act (CEQA), provided that proposed projects reduce GHG emissions, develop multimodal transportation networks, and diversify land uses. This replaced criteria that elevated traffic congestion as a significant impact.”
The strategies of the legislators also intend promote active transportation – walking and bicycling alone, and combined with transit trips – which, through increased physical activity, improves population health.
“The health benefits and harms of specific State of California goals for active transportation have not been quantified on a regional and statewide basis, nor have their potential for health cost savings and carbon mitigation,” the report argues.
From a baseline per capita mean of 40.5 minutes of active travel per week, scenarios increased active travel from 84.5 to 277 minutes per week, “which is approximately the duration of the average California commute in 2010 considering all modes,” the findings indicate.
Dr. Maizlish writes: “The annual number of deaths progressively decreased with increasing levels of active transport: -2,095 for CSMP2020 and -8,057 for USSG1.0. In each scenario, chronic disease reductions were accompanied by increases in the absolute number of serious and fatal road traffic injuries, despite reduced injury risks per mile traveled.
“The annual monetized value of health outcomes through chronic disease reduction were significant, ranging from 1.0 to 59.6 billion dollars, depending on the method of monetization. Holding population and carbon dioxide emissions factors constant at 2010 levels, active transport scenarios were associated with carbon reductions of 3% (CSMP2020) to 14% (USSG1.0).”
His study concludes: “There are large health benefits associated with achieving State active transportation targets. Significant carbon mitigation may also be achieved if increases in active travel are accompanied by concomitant decreases in car travel.
“Active travel generates reductions in chronic disease, and the overall health benefits (and avoided health harms from increased traffic injuries) depend on efforts made to control of road traffic injuries, which are substantially influenced by both active travel mode share and car mile substitution. Achieving mobility- or health-based goals would constitute a major public health achievement on par with California’s successful efforts at tobacco control.”
—David M. Greenwald reporting