Carpooling, once popular, has cut in half since 1980, according to a recent New York Times article:
The sharp decline has confounded efforts by urban planners, who over the years have tried to encourage the practice by setting aside highway lanes for car-poolers, as well as offering incentives like discounted parking.
However, as carpooling has declined, transit use and telecommuting has been on the rise in recent years:
As car-pooling has continued to decline, mass transit use has increased in the past decade. In the Washington area, it represents about 14 percent of commuters, compared with 11 percent in 2000, according to the data.
Another big change has been the number of people working from home at least one day a week, which has tripled since 1998, to about 600,000, according to Nicholas Ramfos, director of Commuter Connections, a network of agencies and local governments that coordinates ride-sharing programs.