1. Code corner
2. A score of 5 signifies that a car's emissions will have an impact on Global Warming equivalent to that of an average new vehicle. A higher score denotes a car that is "better for the environment;See New Calif. Cars to Sport Greenhouse Gas Labels,2008
3. The portion of solid waste recycled in the United States increased from 10 percent in 1990 to nearly 30 percent in 2000, and this is due, at least in part, to the advent of curbside recycling programs. See Thomas C. Kinnamon, Policy Watch: Examining the Justification for Residential Recycling;J. ECON. PERSPECTIVES,2006