US Highway Construction

Timon Singh

Highways are the lifeline of the US economy. Transporting food, equipment, people and other goods, they drive the US economy and are a national necessity and as such, highway construction is always going on.

Currently, there are 5.7 million miles of paved highways in the US with that number ever increasing. In fact, the CIA World Fact Book states that you are never more than three miles from a paved road in 97 percent of the continental United States...one assumes the other 3 percent is most of Alaska.

However, the US's highway network is one that needs constant repair and maintenance, and despite such a budget in President Obama's recent stimulus package, it is felt more is needed to invest in America's highway infrastructure.

Evolution of US roads

America's roads have come a long way since the cobblestone tracks of colonial times. With 8-lane highways, roadside motels, restaurants and service stations, America's roads are an integral part of the country, not to mention the construction industry.

In fact, during the recession whilst other sectors in the construction industry were suffering, road construction and maintenance firms actually saw a growth. The last US highway bill that expired in September 2009 saw $286 billion worth of spending over the previous six years. The new bill is expected to be much more, in the ball park of $450-500 billion.

However, instead of expanding, the focus will be on making the US's roads more efficient and eco-friendly, whilst floundering transportation methods such as rail get a higher percentage of funds in order to relieve the road systems of the large quantities of freight that are transported on the country's highways.

The future of the US's highways

In order to make the US's highways more efficient, ideas have been passed around from the seemingly crazy to the more practical. A factor that everyone agrees on though is making the construction of roads more environmentally friendly.

Currently, for each mile of road constructed, tons of rock, concrete, asphalt and steel are needed, not to mention the gallons of fuel used to power construction equipment. A typical two-lane asphalt road with an aggregate base can require up to 25,000 tons of aggregate rock, showing why aggregates are the most mined resource in the world. However, more importantly, they're a non-renewable resource and as such, highway construction has one of the greatest impacts on the environment.

On top of that, the greenhouse gases emitted from the mining, transporting, heating, earthwork and paving work means that the construction of an average single lane-mile of freeway, produces enough pollution to equal up to 1,200 tons of CO2 - roughly the same amount as the total annual emissions of 210 passenger cars.

With the construction of over 37,000 miles of highway in 2007 alone, it is clear to see why making 'green roads' is of such importance to the construction industry. This has seen the likes of the EPA, Federal Highway Administration, Recycled Materials Resource Center and universities all working on new concepts to make roads more 'green', from form recycling programs for products that include coal fly ash, slag cement and old asphalt or initiatives for storm water management.

Thus far, the results have not been overwhelming but they have been promising. Various innovative and eco-friendly road products have begun to emerge. Thus far, the most promising are soil stabilizers and asphalt binders that provide the equivalent strength of aggregate base rock at a fraction of the cost and environmental impact.

If plans do go ahead, then the US road system could become a sector in which landfill waste can be reused to create roads, but much work is still needed, and to prevent mounting costs and using finite aggregate supplies, the US's engineering, economic and construction firms are going to have to put their foot down and find a solution.

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