Over the past 50 years, the way Americans commute has seen one dominant trend: toward commuting alone by car.
 The percent of Americans who drive a private vehicle to work has increased significantly since 1960. The rapid suburbanization of the United States during the 1960s and 1970s, which some attribute to White Flight after the Civil Rights Act was signed in 1964, may be responsible. America’s love affair with the car certainly didn’t help.
 All these commuters could be carpooling, but as Planet Money points out, the percentage of Americans who carpool decreased from 20% to 10% over the past 30 years. (Despite all the new carpool lanes built.)
 All other forms of commuting became less common from 1980 to 2011 except for working from home. So the only categories that didn’t continually decrease over the past 50 years were “Private Vehicle” and “Work At Home.” We’ll have to wait and see whether the movement for all things green pushes up the numbers of people biking, walking, and using mass transport. But environmental efforts are fighting against longtime commuting trends.