The answers to the question “Why Asphalt” are numerous and varied. For those of you that would like to explore the top reasons for why asphalt pavements constitute the vast majority of paved roads in America, we’re created this short summary document:
Pavement Facts

There are over 4.05 million public centerline road miles (8.52 million lane miles) in the U.S. and of this, 2.50 million miles (or 63 percent) are paved (FHWA 2009). About 70 percent of Washington State roads are paved. Nearly 94% of the paved roads in the U.S. are paved with asphalt surfacing (Asphalt Institute 2014), which is a testament to the enduring value of asphalt roads. An extensive list of AsphaltFacts can be found at the Asphalt.Facts website.
Life Cycle Cost

Today’s current national and local economic conditions – combining reduced funding with high infrastructure needs – have elevated the importance of prudent spending. Decision makers exercising good stewardship practices can easily justify their decisions and choices to their constituents. Good stewardship practices include a detailed, logical, and documented pavement type selection process that includes a life-cycle cost analysis as a key component.
Perpetual Pavement

The Perpetual Pavement concept was first articulated in 2000 and the concept has rapidly gained acceptance. The APA’s newest technical document on the subject is Perpetual Asphalt Pavements: A Synthesis. This comprehensive publication captures the activities that have taken place over the last decade, synthesizes the information in way that is useful to providing guidance for Perpetual Pavement design and construction, and provides a vision for further research and development to refine Perpetual Pavements.
Since the inception of the Perpetual Pavement Awards program, the Washington State Dept. of Transportation has been awarded multiple awards for highways that have 30+ years of service and for new pavements that meet PerRoad perpetual pavement design standards.
Long Life Pavement Renewal resources are also available via the SHRP2Solutions rePave website.
An Article on the Basics of Pavement Design and Perpetual Pavements
Assuming an entirely new road where there has been no pavement before, the process begins with an examination of the right of way and the projected mix of traffic and the expected loading. Then, the soil is prepped, in some cases amended, compacted, and graded (F in the figure). During this stage, drains, sewers, and other features are placed. Next comes the pavement foundation, usually gravel that is placed and compacted (E).
Sustainable Pavement

Asphalt is the sustainable material for constructing pavements. From the production of the paving material, to the placement of the pavement on the road, to rehabilitation, through recycling, asphalt pavements minimize impact on the environment. Low consumption of energy for production and construction, low emission of greenhouse gases, and conservation of natural resources help to make asphalt the environmental pavement of choice. A short video on asphalt sustainability is available here, or read WAPA’s Sustainable Pavement page.
Livable Communities

There is no doubt that societal trends and economic realities will shape the pavement market going forward. Those driving factors include public funding issues, an emphasis on sustainable growth and livability, environmental stewardship, employment trends and future supply/capacity. Accounting for all of these factors, asphalt pavements are perfectly positioned to address the future needs for livable, thriving communities, from freeways to residential streets as well as the other “everyday” infrastructure all around us, such as bike trails paved with porous asphalt.