Advantages :

Carpool participants save money by sharing the cost of driving one car. Driving one car saves on gasoline,tolls, parking and vehicle maintenance.
Carpool lane available.
Carpools decongest roads.
Carpools reduce pollution and carbon dioxide emissions thereby reducing global warming.
Carpools reduces driving-related stress for participants who are not driving on a specific ride. The participants take turns sharing their vehicles and driving with others.
Carpools may provide social connections in an increasingly disconnected society. New online carpooling services are offering new ways to make social connections through discussion sites and custom ridesharing services.
Some larger carpools offer “sweeper services” of late pick-up options for people having to stay longer at work. One form of backup is a “guaranteed ride home” arrangement with a local taxi company.
There are designated carpool lanes on highways (usually called High-Occupancy Vehicle, or HOV lanes), which may make travel faster. Some businesses offer premier parking for carpoolers, and finding a spot to park one car is always easier than finding a spot for more.
In the “dynamic ridesharing” concept the system does one-to-one matching automatically, and all that both, the driver and passenger have to do is accept the match done by the system.





Disadvantages :

Drivers carry the additional burden of potential legal action from passengers in case of an accident.
When carpooling, it becomes difficult to run errands on the way to and from the common locations.
Tends to be complicated to reliably organize and is difficult to maintain, due to changing travel patterns and needs. Sign mark locations outside of their metro stops and large bus stations where drivers can share rides with other passengers in an orderly fashion