Fuel for one car is cheaper than fuel for several cars, and passengers can all chip in when filling the tank.
Fewer cars on the road corresponds to less traffic, which can reduce psychological stress and increase free time, particularly for commuters.
Pavement breaks down quicker the more it is driven on. Better roads lead to less damage to autos from potholes and fewer tax dollars going toward road repair.
Autos emit pollutants such as carbon monoxide, nitrogen oxides and carbon dioxide. The Environmental Protection Agency states that driving a car is probably the typical citizen's biggest polluting daily action. Carpooling reduces this pollution.
Increasing interaction between friends, neighbors and co-workers is a byproduct of sharing rides. This can increase the sense of connectedness within a community.
A 1996 study published in Social Psychology Quarterly on the first carpool lane in Europe found that "solo drivers exhibited a weaker preference for carpooling after the establishment of a carpool lane."
