Roadway Construction Sustainability Impacts

Each year the United States places about $100 billion of roadway construction. This level of activity suggests possibly significant sustainability implications in the construction activities for this work. One means to quantify some of these impacts is through life-cycle assessment (LCA). A review of 14 roadway construction LCA papers reveals some common ideas about the ecological impacts of roadway construction. Some key observations are that (a) the energy expended during roadway construction is roughly equivalent to that used by traffic operating on the facility for 1 or 2 years, (b) total energy use during roadway construction varies but is typically on the order of 3 to 7 TJ/lane mile, (c) total CO2 emissions during roadway construction vary but are typically 200 to 600 Mg/lane mile, (d) materials production makes up 60% to 80% of energy use and 60% to 90% of CO2 emissions associated with construction, (e) construction activities at the jobsite make up less than 5% of energy use and CO2 emissions, and (f) transportation associated with construction makes up 10% to 30% of energy use and about 10% of CO2 emissions associated with construction.