Transportation controls are really needed in the air cleanup fight

The pollutants for which health-based air quality standards now exist include carbon monoxide (CO) and photochemical oxidants. The air quality standard for CO is exceeded in 42 air quality control regions (AQCRs) in the U.S., and the oxidant standard is exceeded in 56 AQCRs. The 66 AQCRs where at least 2 of these standards is exceeded contain about 60 percent of the nation's population. There are now 30 AQCRs in which the new car controls must be supplemented by additional measures to reduce automobile emissions. The additional measures, called transportation controls, can be divided into 2 general classes: measures that reduce in-use automobile emission rates (i.e., emissions/mi traveled) and measures that reduce automobile travel. The former class includes inspection-maintenance and retrofit. The latter includes transit improvements, car-pooling programs, and restrictions on the use of automobiles. The costs, problems, and projected benefits of such measures are discussed.