Slugging

In order to relieve traffic volume during the morning and evening rush hours, high-occupancy vehicle lanes that require more than one person per automobile were introduced in many major American cities to encourage carpooling and greater use of public transport, first appearing in the Washington (D.C.) Metropolitan Area in 1975.

[4][5] Slugging is said to work well in Washington because it is a "unique mix of a small city center, clogged highway arteries, and expensive toll roads".

[16][3] In practice, slugging involves the creation of free, unofficial ad hoc carpool networks, often with published routes and pick-up and drop-off locations.

Drivers pull up to the queue for the route they will follow and either display a sign or call out the designated drop-off point they are willing to drive to and how many passengers they can take; in the Washington area the Pentagon—the largest place of employment in the United States, with 25,000 workers—is a popular destination.

These include:[19] In France, spontaneous carpool lines have been established in rural municipalities by Ecov using electronic signs and smartphone apps to alert drivers of waiting riders.

[22] From 1979 to 1980, Marin County, California, implemented a flexible carpooling system using as meeting points several major intersections near bus stops.

[23] In 2009, the Washington State Legislature set aside $400,000 for a pilot project to test meeting-place based carpooling in the SR 520 corridor of Seattle incorporating the Avego smartphone ridematching system.