Never used it myself but I think it is this: https://sfcasualcarpool.com/ https://sfcasualcarpool.com/ Found that at https://511.org/carpool https://511.org/car

Never used it myself but I think it is this: https://sfcasualcarpool.com/ https://sfcasualcarpool.com/ Found that at https://511.org/carpool https://511.org/carpool which includes a few alternatives as well