Car pooling is simple, tends to be informal, and can last as long as the participants choose. Car pools are based on sharing commute expenses. Poolers use one car owned by one driver. Poolers can rotate car use and driving, so that each person's vehicle and time are shared equally. No money is exchanged in this arrangement.
Many car pools begin informally between neighbors or co-workers.
Other car pools are initiated with the help of employers and the T, which can match commuters based on work hours and geographic location. This car pool matching assistance through the T is free. Once commuters find someone whose schedules and locations are compatible, the next step is to meet the potential car pooler to discuss arrangements. Each individual car pooler can leave the pool during the trial period if they so desire. Once the car pool is set, courtesy dictates that participants who decide to leave give advance notice to their car pooling partners to minimize inconvenience.