Infrastructure as a Tool for Sustainability

Michael Milligan
4 min readJan 31, 2022

Infrastructure is the backbone of our lives — from the roads and bridges we travel, to the energy and water that fuels our families. In its 2021 Report Card for America’s Infrastructure, the American Society of Civil Engineers (ASCE) graded U.S. infrastructure with a C- overall, up from a D+ in 2017. While the state of infrastructure in the U.S. has much room for improvement, I see several reasons to believe in a brighter future, one focused not only on safety, but on sustainability.

ASCE finds the overall grade for U.S. infrastructure by individually rating aviation, bridges, dams, drinking water, energy, hazardous waste, inland waterways, levees, ports, public parks, railways, roads, schools, solid waste, stormwater, transit and wastewater. They then average those grades to find the final overall grade, just like in school.

Sustainable infrastructure options are key for future development.

ASCE, an ABET member society, has been working hard over the past decade to advocate for legislation supporting investment in infrastructure. Recently, Congress passed the $1.2 trillion Infrastructure Investment and Jobs Act, signing it into law.

“This is a historic time for our country, and ASCE’s members should be proud they played a substantial role in getting this bill crafted and passed,” said ASCE President Dennis D. Truax, Ph.D., P.E., D.WRE, F.ASCE, in an article in Civil Engineering Source. “This success has its foundation in over two decades of investment in the Report Card for America’s Infrastructure program. Recognized as ‘honest brokers’ focused on life, health, and safety of the public, ASCE’s advocacy efforts helped us see this day come.”

This bill contains funding to make our infrastructure more sustainable, which means these structures will provide for our needs now, but also with consideration for how they will impact future generations.

Planning for Sustainable Development

A good example is a roundabout, a more sustainable type of intersection than those with a traffic light or stop controls. While roundabouts are not common in the U.S., many countries worldwide make effective use of them. For example, the U.S. has 100 fewer roundabouts per one million inhabitants than Germany.

A graph of 10 countries showing the number of roundabouts per one million inhabitants.
According to Statista, the United States is behind many other countries in its use of roundabouts.

Roundabouts tend to be safer, cheaper and better for the environment than other types of intersections, according to the U.S. Department of Transportation. They also tend to keep traffic moving faster than signalized or stop-controlled intersections, allowing goods and services as well as commuters to be transported more quickly. Taking sustainability factors such as these into consideration as we improve current U.S. infrastructure could help us improve our roads, which received a D on the ASCE report card.

One benefit to the environment is the green space roundabouts provide. Not only does this help filter the air, but roundabouts also help reduce the pollutants that are going into the air in the first place. Because roundabouts use yields rather than stops, vehicles spend less time idling. There is also less stop-and-go, which can cause vehicles to use additional gas than when cruising at a consistent speed, resulting in fewer emissions polluting the air.

Roundabouts also don’t require any electricity. There are no light bulbs to replace, no equipment to repair and no lights to power. There is also no equipment to fail during a heavy storm. In fact, no matter the weather or state of electricity, roundabouts function the same.

Roundabouts have been a success in other countries. Perhaps they will also benefit infrastructure in the United States.

Even on a regular day, roundabouts are safer than a traffic light or stop-controlled intersections. According to the American Association of State Highway Transportation Professionals’ Highway Safety Manual, fatal and injury crashes are reduced 82% when a roundabout replaces a two-way stop intersection and 78% when a roundabout replaces a signalized intersection. There are 32 potential vehicle contact points in a typical intersection but only eight in a roundabout. The potential for fatalities and injuries decreases because those contact points are now at an angle, reducing the force of the collision compared to a direct hit. Roundabouts also force drivers to reduce speed, lessening the impact even further.

As this example shows, even seemingly small choices in infrastructure planning can make a dramatic difference in sustainability. If just a change of intersection designs can impact sustainability, imagine what we can do as we improve other, more substantial forms of infrastructure. My hope is that we’ll keep sustainability in mind as we rebuild and improve our global infrastructure.



Michael Milligan

Executive Director & CEO of ABET, the global accreditor of college and university programs in the STEM disciplines.