Carbon Dioxide Production (image) University of Washington Caption This is a comparison of carbon dioxide produced per customer for personal vehicles and delivery vehicles. The bars on the left represent a system in which customers choose their delivery times. The right side shows a more efficient system whereby the delivery service sets delivery times. Credit Goodchild/Wygonik, UW Usage Restrictions Photo credit required Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.