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6 Signs that Mark the Path to Sustainable Road Design

The United States highway system puts Roman roads to shame as the largest public works project in the history of man.  With an approximate cost of $425 billion, the government’s reluctance to abandon the network of roads and highways that provide low cost per capita transportation to the country is completely understandable.  Although mass transit is demonstrably more sustainable than the continued reliance on motor vehicles as the primary means of transportation, a complete and immediate shift to buses and trains is not only logistically impossible but also culturally infeasible.

Simply put, people are going to keep driving cars, which means we’ll always need roads.  Recognizing this fact, a growing group of advocates has chosen to address the negative environmental impact of poorly planned roads by suggesting the adoption of a road rating system similar to the system LEED (Leaders in Energy and Environmental Design) uses for buildings. Though buildings only have a point source impact, and roads have both the point source impact and a linear effect (since roads run through the landscape), the principles are essentially the same. By using preset categories to award points for sustainable design, programs like Greenroads (Washington) can provide a system for incentivizing sustainable design.  In addition, by defining and classifying elements for benchmarking, incentives can be structured to promote environmentally sound solutions. Finally, establishing reputable metrics for comparison will facilitate endorsement of sustainable projects over those without low impact elements of design.

For a road rating system to work effectively, the grading categories will have to be well defined, understandable to the public, and be irrefutably beneficial in terms of sustainability. Martina Soderfund, whose thesis paper sparked the Greenroads project, suggests six categories for a proposed rating system:

1. Sustainable Alignment

For most roads, cost of construction is the highest priority determinate of path.  However, including this category in the consideration of sustainability ratings would add additional points for roads that avoided certain habitat types, such as wetlands, forests, farmlands, or other ecologically sensitive areas.

2. Materials and Resources

Asphalt, gravel, and tar have a high environmental footprint due to extraction, transportation, and use.  The materials and resources category would reward projects that made efforts to reduce these impacts.

3. Stormwater Management

Seldom recognized by the general public, the continually increasing percentage of impervious land cover has negative implications for stormwater runoff and management.  Promoting stormwater quality and quantity control through this category increases awareness of road impact and encourages the use of pervious surfaces.

4. Energy and Environmental Control

This category addresses some of the more subtle and inherent effects of typical roadway design.  It evaluates the quality of design, while considering effects on light pollution, the heat island effect, quieter pavements, eco-viaducts (wildlife and fauna crossings), visual quality, and pedestrian/bicyclist access.

5. Construction Activities

The temporary activities of the roadway construction are a major source of pollution, waste, energy use, and health issues.  Major concerns of this section can be categorized as: site disturbance, waste materials generation, noise pollution, emissions & energy usage, and the health of workers.

6. Innovation and Design

The credit definition of the last section is awarded for additional performance above the requirements set in the previous sections.  Consider it extra credit or bonus points for exceptional performance in a particular category.

Regardless of how high of a priority sustainability is becoming, we will be using roads for years to come.  Instead of throwing up our hands in defeat at the environmental impact they produce, forward thinkers encourage attempts to mitigate impacts.  Although a rating system would be flawed, just as LEED is, any attempt to improve road sustainability would be better than nothing.

Emily McClendon is an environmental marketing specialist currently working at NeboWeb. She has a B.S. in Applied Biology from Georgia Institute of Technology and is currently pursuing her M.C.R.P. in Environmental Planning, also at Georgia Institute of Technology. She believes that communication and shared knowledge are the most important facets of conveying environmentally friendly practices. After participating in biological research, inter disciplinary planning, and interactive marketing, she is convinced a comprehensive approach is the only solution for creating a sustainable economy.

Emily McClendon
Emily McClendon is an environmental marketing specialist currently working at NeboWeb. She has a B.S. in Applied Biology from Georgia Institute of Technology and is currently pursuing her M.C.R.P. in Environmental Planning, also at Georgia Institute of Technology. She believes that communication and shared knowledge are the most important facets of conveying environmentally friendly practices. After participating in biological research, inter disciplinary planning, and interactive marketing, she is convinced a comprehensive approach is the only solution for creating a sustainable economy.
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21 thoughts on “6 Signs that Mark the Path to Sustainable Road Design

  1. Though still a young organization, the Institute for Sustainable Infrastructure is working towards a LEED type certification for infrastructure projects.

  2. This sounds great but most of the talking points are about the construction aspects of roads. Sure this would reduce environmental impact slightly, but the largest impact of roads is how they are used, not how they are built. An empty road does not continue to pollute and destroy, it is the vehicles using it that are the problem. In my opinion a rating system like this needs to be targeted at construction sustainability in general, rather than just road construction. The only way we are going to reduce the negative impacts of our transportation system is implementing significant changes to our land use policies and patterns.

  3. Yes, of course this is a good idea. However, it runs the risk of missing the point in a big way. Is it sustainable to build a LEED Gold 10,000 s. ft. mansion? To only measure motor vehicle performance and ignore transit is a potentially similar focus on details while ignoring the big picture. It runs the considerable risk of making us feel good while we continue our worst habits. Emerging automated transit network systems are now proving very succesful. Studies are showing that these systems can attract drivers from their cars in significant numbers. The system you are proposing MUST address all forms of transportation or it will perpetuate unsustainable practices while giving the preception of sustainability. This could be worse than doing nothing.

  4. Interesting thoughts. Let me share a bit of history and a few additional thoughts. Lochner and others have been working on such programs now for a number of years. We developed a comprehensive rating program very much like what is described. Marketing it however has been a significant challenge for two reasons.

    First, in spite of what some in the environmental community might say, there already is a strong move, and has been for many years, by engineers to build sustainable roads. Those of us who have also had the responsibility to maintain them find that a necessity for economic reasons as well as a strong desire to build facilities that work within the environment. For example the use of LED lighting is a clear winner in long term costs, particularly as the effectiveness has improved and initial cost decreased. I’ve often heard it said “We are already doing that, so why do we need another layer of (expensive) process to justify it?”

    Second, the reality is that there must be some type of financial incentive for those government agencies who actually build and maintain our transportation networks, and who are already working on thin margins, to add cost to a project. Those agencies are, and generally always have been, unable to build and maintain the infrastructure to a functional level that many would desire, so added costs must be clearly warranted, and in a manner that the public supports that cost. Citizens are pretty clear that they want environmentally friendly facilities, but give short shrift to what they might see as feel good options or gold plating.

  5. Concerning the materials for road construction, tar is not an ingredient. The extraction of crude oil and creation of liquid asphalt cement plus the extraction and readying of aggregates for an asphalt pavement combined has a marginal carbon footprint, especially when modern technologies such as the use of warm-mix asphalt and recycled materials are used. The carbon footprint is incredibly lower than that of alternative pavement choices, which you can see for yourself at http://www.asphaltroads.com.
    Concerning the completed roadway’s long-term carbon footprint, the smooth nature of the asphalt pavement has proved to reduce fuel consumption for motor vehicles traveling on it, thus lowering the pull on natural resources from the traveling public.
    Using a sustainable product such as asphalt pavement makes good sense for LEED projects from start to finish…and beyond.

  6. While LEED type certification seems wonderful and green, I believe it would be much more effective if the funds used to obtain such certifications were instead put into the actual design, construction and operations budgets. Obtaining certifications has grown into it’s own industry, one that in my opinion siphons off resources better used to maintain sustainability.

  7. Just thought you might desire an update from the Greenroads folks. Martina’s paper was an excellent starting point for our research but we have come a long way since then. Right now we are on version 1.5 of the Greenroads Rating System and will likely certify our first project through our non-profit Greenroads Foundation next week. Greenroads 2012 is due out this year, which will incorporate bunches of changes based on what we’ve learned and heard from everyone. We’ve learned lots along the way and we continue to learn more every day from the people in our industry. Here’s a brief review of a few of those things:

    1. A more sustainable road costs less. Sustainability is not an add-on feature. It’s at the heart of what we do in infrastructure. When you consider the whole cost, over the life of the facility, a more sustainable solution costs less.

    2. A rating system does not define one’s approach to sustainability. Rather, a savvy organization that has a good approach can use a rating system like Greenroads to help them ensure their strategic emphasis on sustainability is actually showing up on projects.

    3. Often, rating systems are a great list of ideas to help get the sustainable blood flowing in design and construction.

    4. Driving on roads does consume a lot of energy and produces lots of emissions. A good rule-of-thumb is this – the energy required to construct a road is roughly equivalent to the energy expended by all the traffic driving on it over a 1-2 year period. So, sure, the materials that go into the road are not the only consideration. However, roadway design and construction can greatly influence use, durability, stormwater, environmental impact, etc.

    5. Rating systems help communicate sustainability. If they’re done well they can communicate it to the general public, amongst a project team and within an organization. That communications aspect is critical. Let’s face it, as engineers we are not known for our marketing or communications prowess.

  8. You have some very good ideas in this article, but you (and our government) are missing the most important part which could be listed as #7- Preserving and maintaining our infrastructure. You cannot build it and forget about it. Even the most sustainable road design must be preserved and maintained which in turn makes roads last even longer.

  9. Life-cycle cost to the taxpayer also involves more than contruction, operation and maintenance. Safety (crash avoidance), delay and fuel consumption are also items the users pay for that could be reduced by the roadway design.

  10. The 6 criterias for roads are well picked. However anyone who has built roads knows that what precedes the roads is sometimes the most important factor economicaly and environmentally: Infrastructure- water mains, sanitary sewers, cable TV, electrical lines overhead and underground, gas lines, telephone lines, and other communication lines. These are the most disruptive and time-consuming construction wise. They should be addressed before any road is started.

  11. If you eliminate wetlands, forests, farmlands, or other ecologically sensitive areas from road building, what is left except building on top of existing roads. What is needed is a holistic approach that recognizes the various considerations needed to achieve sustainibility. If the federal government doen not fix the Highway Trust Fund or replace it, the environmentalists will get there way and road building will eventually cease. Total asset mgt on a life-cycle basis would get you a long way towards sustainability.

  12. Anything to provide a source of sustainable ideas is an improvement. I’d hope to see vehicle flow as a key factor, much in the way LEED considers HVAC design and subsequent monitoring as a factor. Reducing vehicle congestion, such as a providing roundabouts instead of 4-way stops where appropriate, and incorporating updated models to aid flow of traffic through commonly congested areas (minimize peak flow demand by improving vehicle fuel efficiency to design speed, not stop and go speed) should be one of the goals. Effort such as incorporating accel/decel lanes into the design is just the first step into addressing a significant aspect of the long term sustainability of roads- that is to better support the efficiency of vehicles that will use them after construction. Discouraging use of roads (as I read into some comments) should not be an engineering consideration, but a policy decision through other efforts such as regulations, fees, and fuel taxes.

  13. Are you kidding?
    Scoring facilities by a point system, imagine the political bias in that game?
    Life costing and economic value and public value is and always has been evaluated on construction projects.
    Sustainablity of what, do you suggest also that we keep it organic?
    Another example of the nonsense being created by self vested interest groups.

    lifestyle value

  14. It’s about time environmental foresight is integrated into infra design, particularly roadways. A decade ago we conceptualized a “constructed roadways and wetlands for traffic and rainwater management”. Now it is mandated in most new national roads in the Philippines. The schematics of upsides and downsides can be sorted out as we move along. The important thing is there is one eye focused on the sustainability of the ecosystem.

  15. An additional category for awarding sustainability points should be the destination endpoints for the roads. Specifically, there should be absolutely no exits or intersections constructed in undeveloped areas. This will minimize sprawl. Roads don’t go where the people are; people go where the roads are. Encourage linking high population density areas. This will encourage building up, not out, and maximize intra-city public transportation at the lowest cost.

  16. Good idea with the rating system. There should also be a rating system for road resurfacing. To often this is rushed and sloppy work is done. Roads are esential to keep the infrastructure of the United States competive. Better roads reduce fuel usage, flat tires and other damages.

  17. In the UK we use a methodology called CEEQUAL to assess the sustainability of infrastructure projects. It considers many of the factors highlighted above.

  18. Sustainability concerns for pavement design are a very good thing so well done in the article. But it is the ongoing sustainable and environmental benefits that have to be considered as well. Concrete pavements offer Real Fuel savings, aggregate savings of up to 50%, huge CO2 reductions, lighting/energy savings, lower vehicle operating costs, lower cost to construct, own/use and recycle at end of life, – all of these savings and reductions need to be identified and quantified to get a true idea of the viability of the best materials. ARA, MIT, Athena and more all have excellent third party studies and information all concluding that concrete is the best material. Crude comes by Ocean shipping which is responsible for 5% of global CO2. Many Oil producing third world countries have their people living in poverty and doing so on oil sodden earth (Crude World by Peter Maass). As a first world society we must be fully aware of these things, not just pay them lip service. LEED certifies a building based on materials, methods and expectations – we need the same for pavements – based on fact and science, certainly not politics and not on what some are just confortable in designing.
    More and more people are beginning to understand what the future really holds and it is everyone’s responsibility.

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