Zipcar offers a membership service that allows you to easily join and access a network of shared vehicles for convenient, on-demand car rentals by the hour or day, providing a flexible alternative to car ownership.

https://www.zipcar.com/join

The Traffic Solutions page on the Emergency Ride Home (ERH) program describes a service that provides free rides home for commuters who use alternative transportation methods and encounter an emergency.

https://www.trafficsolutions.org/erh/