Means by which an estimated 8,000 to 10,000 morning commuters enter San Francisco from the East.

This informal system has existed since HOV lanes on the Westbound approaches to the San Francisco Bay Bridge allowed carpools to bypass the toll plaza, but rising transit fares and strikes in the 1990s made it a more popular option.

Most users list the time saved as the biggest option. Riders save money (BART is $2 or more, and the Transbay bus service by AC Transit is $2.50), and some time on their commute (although usually have to walk or bus it once they hit downtown SF). Most of the riders would otherwise take public transit (and do on the way home, making Eastbound commutes in the evening are more crowded)

There are some commonly understood "unwritten rules" of the casual carpool.

  • You don't talk.
  • You don't smoke. You don't eat. You don't bring coffee.
  • Drivers may break any of the above rules. Riders may not.
  • The driver sets the radio station.
    Most newspaper accounts of casual carpooling note the predominance of KQED, the NPR affiliate. (In my neighborhood in Oakland, it's 50% NPR, and 50% KBLX, an R&B station featuring a specialty call-in "battle of the sexes" on their morning program.)
  • You only fill the car to three people, unless the driver indicates otherwise. Taking a fourth "steals" a passenger from the next car in line. (However, when there is a shortage of cars, and a surplus of passengers, the understanding driver will invite another person in.)
  • Your driver will exit I-80 at Fremont Street or Harrison. You're supposed to get out at Fremont and Howard, but some drivers will offer to take you a few blocks more to Mission, or Market, where they will double park, let you out at a stop light, or pull over in a no stopping zone.
  • You don't get a ride home. There is an Eastbound casual carpool, but logistically, it's more difficult to find a driver going your way. (The HOV on-ramp is very short and difficult to get to, plus there's no toll eastbound) Between 3:30 and 7 PM weekdays, passengers and drivers can connect at Beale Street between Howard and Folsom.
Although the system is self-perpetuating, and not organized by any local or regional authority, local communities usually designate areas for morning pickups.

Locations to try this:

  • Emeryville: Powell St, just west of I-80/Frontage Road (eastbound side, adjacent to bus stop).
  • Richmond: Richmond Parkway Park and Ride. Richmond Parkway just west of I-80. Caution: the lot fills early (7 AM). You may be towed if you park in the adjacent shopping center lot!
  • Moraga:Moraga Way. North side of Moraga Way, west of School Street.
  • Oakland
    • Lakeshore & Grand. Under I-580 in Park and Ride lot, on the left as you enter.
    • Grand & Perkins. On the north side of Grand, by the Shell sign next to AC Transit stop.
    • Claremont & College By the Union 76 gas station on the north side of Claremont.
    • Park & Hollywood. Adjacent to TransBay bus stops on Park between Trestle Glen and Hollywood.
    • Park & Hampel. Near TransBay bus stop on Park and Hampel.
    • Fruitvale & Montana. Just north of Park and Ride lot on Montana by Flagg.
    • Hudson & Claremont. Under Hwy 24 on Hudson, just before Claremont.
    • Oakland and Monte Vista. At the intersection of Oakland and Monte Vista.
  • Piedmont:
    • Oakland and Hillside. On Oakland Ave, just east of Hillside.
    • Oakland and El Cerrito. On Oakland Ave, just west of El Cerrito.
  • Berkeley:
    • North Berkeley BART. On Sacramento, east of the entrance to the BART station.
    • See Oakland: Claremont & College.
    El Cerrito:
    • El Cerrito Del Norte BART. On Eastshore, just south of FoodsCo.
    • Pierce and Central. On the west side of Pierce, a few hundred yards south of Central.
  • Lafayette: Lafayette BART. North of the station, just outside and to the right of the parking lot.
  • Orinda:Orinda BART. In the alley on the north side of Theater Square.
  • Hercules: Park and Ride. In the lot, near 80 on San Pablo Ave, just north of Sycamore.
  • Vallejo: Park and Ride. In the lot, just west of 80 at Curtola Parkway and Lemon.
Source for list of locations: Environmental Defense Fund at, which is odd when you realize that casual carpooling doesn't reduce traffic and its consequent air pollution, it merely shifts passengers from transit into cars.