That was the first year the U.S. Census Bureau began collecting data on car pooling. The latest figures show a distinct drop.
"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.
They thought they were getting some help from amendments to the Clean Air Act in 1990 that would have required many companies to develop plans to increase car-pooling and mass transit use. But Congress, after hearing from critics who said the proposal was unworkable, scrapped the idea in the mid-'90s."