Slugging

Slugging, also known as casual carpooling, is the practice of forming ad hoc, informal carpools for purposes of commuting, essentially a variation of ride-share commuting and hitchhiking. Typically slugging is motivated by an incentive such as a faster HOV lane or a toll reduction. While the practice is most common and most publicized in the congested Washington, D.C. area, slugging also occurs in San Francisco, Houston, and other cities.

Read more about Slugging:  Background, Etymology, General Practices, Other Countries