- Traffic lights have a significant carbon footprint
- The carbon footprint of roundabouts is close to zero
- Roundabouts qualify for The California Environmental Quality Act (CEQA)
- Roundabouts will significantly reduce negative impacts on noise and air quality
- Roundabouts reduce fuel consumption
- Roundabouts have no signal equipment or overhead lights to install, power and maintain
- Roundabouts are in compliance with our dark sky mandate
- Roundabouts will help maintain the Covenant’s rural character

According to the Federal Highway Administration:

Roundabouts often provide environmental benefits by reducing vehicle delay and the number and duration of stops compared with traffic signals. Even when there are heavy volumes, vehicles continue to advance slowly in moving queues rather than coming to a complete stop. This can reduce noise and air quality impacts and fuel consumption significantly by reducing the number of acceleration/deceleration cycles and the time spent idling.

Kansas State University (Environmental Impacts of Kansas Roundabouts, September 2003) at three different locations that were converted from four-way stop control intersections to modern roundabouts, found:

- 38-45 percent decrease in Carbon Monoxide emissions
- 55-61 percent decrease in Carbon Dioxide emissions
- 44-51 percent decrease in Nitrogen Oxides
- 62-68 percent decrease in Hydrocarbons

In addition:
- Traffic light intersections will require 8-250W overhead flood lights with 4000 lumens
- No signal equipment to install, power, and maintain.
- Less pavement needed because additional pavement width is not needed for turn lanes.
- Carmel, Indiana city officials report that their roundabouts save 24,000 gallons of gas a year