There are no car sharing services in Palo Alto, but you should know that Enterprise has (or at least used to have) an hourly rental service on the Stanford campus. It's not quite the same thing, but would do in a pinch.
Palo Alto is also remarkably walkable if you stay near downtown - there is even a train directly to San Francisco.
Palo Alto is also remarkably walkable if you stay near downtown - there is even a train directly to San Francisco.