Engineering Group Takes on High Speed Limits
“The National Committee on Uniform Traffic Control Devices, a powerful group of engineers, voted last week to require city transportation officials to consider “pedestrian and bicycle activity” when determining the speed limit on most urban and suburban streets.” As the study below indicates, this would reduce emissions (though cars are typically designed to operate most efficiently within a set range of speeds). Read the article.
By Angie Schmitt, StreetsBlog USA, Jan 18, 2019

The effect of vehicle speeds on emissions
As vehicles travel faster, the energy required to overcome aerodynamic drag increases approximately exponentially, and becomes the dominant term in total fuel use…The results suggest that 3.1% of car CO2 emissions could be saved if current speed limits were enforced, or 7% if a maximum limit of 50 mph were imposed.
Malcolm Fergusson, Energy Policy Volume 22, Issue 2, Feb 1994, Pages 103-106