Driving Innovation: Accelerating Toward Sustainable Roads

Roads are essential for connecting communities and driving economic growth. However, conventional transportation infrastructure comes at an environmental cost. The good news is sustainable roads are on the horizon as the world shifts toward a greener future. 

Through innovative design, eco-friendly materials, and the latest technology, the United States can build safer roads for the planet. Here are the environmental impacts of traditional roads and ways to make highway construction more sustainable. 

The Environmental Impact of Roadways

The United States has 4.17 million miles of roadways, which drivers use to get from Point A to Point B. Often, people fail to consider the environmental impact of so much infrastructure amid the convenience of travel. 

The expansion of pavement has significantly contributed to habitat loss for numerous species, driving wildlife toward dangerous collisions with moving vehicles. Americans hit over 1 million large mammals like deer and elk annually. Another 365 million smaller vertebrate animals — birds, coyotes, raccoons, possums and foxes — also suffer painful deaths from transportation.

Unfortunately, traffic has put 21 threatened and endangered species — such as the Hawaiian goose and Houston toad — at risk of extinction in the U.S. alone.

Road construction also leads to nonpoint source pollution and severe erosion, emitting harmful toxins — heavy metals, oil and other substances — into sediment and waterways. With all the damage caused by transport infrastructure, it is crucial to consider sustainable roads in the future.  

7 Ways to Achieve Sustainable Roads

Sustainable roads are no longer a distant dream for construction experts and infrastructure specialists. Today, society has the means, knowledge and resources to transform roadways into green highways. Here are seven ways the U.S. can achieve sustainable road development. 

1. Use Recycled Materials

Traditional road construction uses asphalt and concrete, producing greenhouse gas emissions that impact climate change. In fact, the particulate matter (PM2.5) from asphalt — derived from crude oil — is higher than PM2.5 from vehicles and trucks. 

Asphalt is even more dangerous when heated. When asphalt reaches 60 degrees Celcius — 140 degrees Fahrenheit — on a hot and sunny day in Los Angeles, semivolatile organic compounds escape into the atmosphere.  

Instead, roadway construction should include reclaimed or recycled pavement, concrete aggregate, and bio-based alternatives, which are just as durable but environmentally safe.

2. Implement Sustainable Drainage

In Makueni County, Kenya, city engineer Michael Maluki plans to improve drainage systems to create more sustainable roads. The county has already installed drains to draw water through channels and irrigate nearby crops. They also created makeshift dams where roads cross over rivers to capture upstream flows during the rainy season. 

The U.S. should consider similar ways to implement better drainage into roads and highways. For instance, permeable pavement allows water to seep through, minimizing erosion and pollution from runoff. Other ideas include mimicking natural channels and building temporary water storage, allowing it to evaporate or infiltrate the ground in time.

3. Plant Vegetation

Trees sequester ample carbon dioxide from the atmosphere, helping to temper the effects of global warming. Planting trees — preferably native, low-maintenance flora — along roadways to absorb carbon emissions from traffic and noise is crucial. 

Vegetation also soaks up rainwater flooding from roadsides and restores habitat for various pollinator and avian species. Additionally, social benefits include improved aesthetics, especially near urban areas. 

4. Integrate Smart Road Technologies

One might forget how roads utilize electricity through traffic lights and cameras. Fortunately, the latest technological developments make energy efficiency and transportation management easier to attain.

Sensors can optimize traffic flow, reduce roadway congestion and enhance fuel efficiency. For instance, a car idling in a traffic jam produces much higher emissions than driving. When numerous cars are in standstill traffic, greenhouse gases can be highly detrimental.  

Likewise, installing solar panels or piezoelectric transducers — materials that generate electricity from mechanical pressure — are other ways to meet energy demands.

5. Include Noise-Reducing Surfaces

Many people forget about noise pollution, but it can harm people and wildlife, such as car horns, pavement tire movements, and engines rumbling. In fact, listening to noises above 80 A-weighted decibels (dBA) can cause hearing loss temporarily or permanently. 

The inside of an airplane or an alarm clock is 80 dBA. In comparison, a lawn mower or hair dryer is 90 dBA, while a motorcycle or construction site is 100 dBA. If these everyday sounds can cause so much damage to a person’s hearing, imagine what it can do to an animal living in the woods surrounding the highway. 

6. Factor in Wildlife Crossing

Habitat fragmentation is a serious problem resulting from road construction. To enhance highway sustainability, engineers should construct wildlife crossing structures. 

According to a May 2021 Forest Service report from the U.S. Department of Agriculture, wildlife crossings are associated with a 97% reduction in wildlife-motorist collisions, protecting humans and animals alike. 

Wildlife crossing structures are essentially passageways for animals to move safely from one side of the street to another. They may be an opening under a highway or a designated wildlife bridge extending over the road. Some are designed for a specific species, such as moose, elk, deer or those with a concerning population status. 

One example is State Highway 21 by Lucky Peak Reservoir, Idaho — an underpass serving as a key habitat crossing for deer and elk. Ultimately, there were fewer collisions between drivers and animals. 

7. Employ Preventative Maintenance

Maintaining existing roads is just as crucial as building sustainable roads for the future. Inspecting pavement for cracks and sealing potholes immediately prolongs its life span, decreasing the need for additional resources, energy and reconstruction.

Likewise, repairs may entail sustainable practices and techniques, such as using aggregate, recycled and reclaimed materials. 

By reducing the need for entire road replacements and new highways, officials can reduce traffic congestion and emissions caused by disrupted infrastructure.

Taking the Road Less Traveled for Greener Transportation

Sustainable roads may be a newer concept than traditional highway engineering, but they are the path to a greener future. As electric vehicles become more prevalent, roadways must keep up with the trend. Drivers should buckle up for environmentally friendly changes regarding new road construction.