Greenhouse Gas Emissions from Duke University Employee Commuters: The Cost-Effectiveness of Reductions

Abstract

Duke University is seeking to decrease greenhouse gas emissions from its employee commuters. I build a linear optimization model to predict Duke University and Medical Center employee commute mode share. Combining these results with a forecast of Duke employee growth, I calculate the impact on employee commuter greenhouse gas emissions of 1) existing Duke carpooling and bus subsidies, 2) a $10 per month increase in employee parking costs and 3) a $20 per month increase in employee parking costs. The cost-effectiveness of these measures in 2015 to Duke University is $309.96 per mtCO2e for existing policy, -$248.87 per mtCO2e for a $10 per month increase in parking costs and -$516.21 per mtCO2e for a $20 per month increase in parking costs. Including costs to commuters, the cost-effectiveness of these policies to society as a whole is $57.41, $84.18, and $399.82 per mtCO2e. From the perspective of Duke University, excluding costs to employee commuters, the existing policy scenario is the least cost-effective strategy for achieving greenhouse gas emissions reductions from employee commuters. The parking cost increases are the least cost-effective when costs to employee commuters are included. From this combined perspective, the existing policy scenario is the most cost-effective policy.