Asphalt Pavement Magazine - January/February 2015 - (Page 48)

The Importance of Building Smoother Pavements Smoother pavements reduce rolling resistance, which improves fuel economy By Amlan Mukherjee, Ph.D., and J. Richard Willis, Ph.D. E nergy, natural resources, and fuel consumption are all part of the bigger picture of sustainability and climate change. It is a crucial discussion as the demand for fuel has continued to grow. In 2011, almost 71 percent of the petroleum used in the United States was used in the transportation sector, accounting for 27 percent of U.S. energy demand. Despite a 50 percent increase in the overall fuel economy of passenger vehicles between the years 1973 and 2000, the average fuel economy of heavy vehicles increased less than 20 percent to only 6.2 miles per gallon. In this same time period, the annual mileage driven by heavy trucks increased by 64 percent1. Meanwhile, consumers, governments, and state agencies are all seeking ways to become more sustainable. One area in the field of sustainability relates specifically to vehicle fuel economy because it directly impacts all three facets of the triple bottom line sustainability principle: social, environmental, and economic benefits. If the fuel 48 * View past issues online at economy of vehicles increases, fewer natural resources will be required to produce fuel, and vehicles traveling on the roadway infrastructure will produce lesser volumes of greenhouse gasses, and consumers who traverse the highway network will save money. Pavement Vehicle Interaction While this might seem like a simple concept, understanding the factors that affect vehicle fuel economy is complex. It has spawned several field studies dedicated to understanding pavement vehicle interaction (PVI) and its role in reducing pavement life-cycle emissions. Energy losses at the PVI interface due to rolling resistance, aerodynamic forces, inertial forces when accelerating, internal frictional forces, and gravity when driving on slopes, must be overcome in order for vehicles to move. These forces can be further broken down into rolling resistance, air resistance, inertial resistance, gradient resistance, side force resistance, transmission losses, losses from the use of auxiliary equipment, and engine friction. This becomes more complicated when one

Table of Contents for the Digital Edition of Asphalt Pavement Magazine - January/February 2015

Chairman’s Commentary
Industry News
PaveXpress: A Simplified Pavement Design Tool
Sustainability Section NAPA’s Asphalt Sustainability Conference
The Federal Highway Administration Sustainable Pavements Program
Environmental Product Declarations in the Sustainable Marketplace
Examining the Use of Reflective Pavements to Mitigate the Urban Heat Island Effect
Pavement Vehicle Interaction and Smooth Asphalt Pavement
The NAPA Diamond Achievement Sustainable
Beyond Compliance: Achieving EH&S Excellence
A World of Asphalt Preview Section the World of Asphalt Education Program: Laying the Base for Innovation
Tools for the Trade
Industry Events
Index of Advertisers/

Asphalt Pavement Magazine - January/February 2015