During the past four years, U.S. infrastructure has improved from a grade of D to D+, according to a report by the American Society of Civil Engineers (ASCE). Despite the slight progress, the report concludes that the country's infrastructure needs $3.6 trillion in investment by 2020 to bring it to an acceptable level; $2 trillion in spending is projected.

Every four years, ASCE releases its Report Card for America's Infrastructure, which uses a committee of more than 30 engineers to assign letter grades based on capacity, condition, funding, future need, operation and maintenance, public safety, resilience and innovation. None of the categories examined for the 2013 report declined compared to 2009. Six of the 16 categories — bridges, drinking water, rail, roads, solid waste and wastewater — scored slightly better. Some categories improved because of short-term increases in federal funding. Rail went from a C- to a C+ due to increased private investment for efficiency and connectivity. Aviation, dams, energy, hazardous waste, inland waterways, levees, public parks and recreation, schools and transit maintained the same grade. Ports were evaluated for the first time.

Solid waste received the highest grade of B-, an improvement from the C+ it received in the three previous reports. The report found that while capacity is an issue in some local areas, landfill capacity at the national level is sufficient. Also, the recycling rate has increased from less than 10 percent in 1980 to 34 percent in 2010. One area of concern is the disposal of used electronics. Overall, the report concluded that technology and recycling have successfully improved the safety, sustainability and efficiency of the waste disposal system, but that the under-use of waste-to-energy practices demonstrates the need for the development of new policies and practices.

Levees and inland waterways both received the lowest grade of D-. The federal government directed significant funding to the system in New Orleans and California has invested in its levees, yet of the estimated 100,000 miles of levees, the average age is 55 years old. One recommendation is to establish a National Levee Safety Program that would require safety inspections and map flood-prone areas. According to the report there is an average of 52 service interruptions daily throughout inland waterways. Suggestions for improvements include boosting funding by increasing the barge fuel tax or implementing a user fee.

The report also includes state report cards; charts and figures, such as the Top 10 U.S. Passenger Airports; and details of the grades. This marks the first time since 1998 that the grades rose overall and in several sectors.