I see the basic fleet management principles as very similar. In both cases, you need the right vehicles, in the right condition, available when customers need them.
The main difference, in my view, is the operating model.
First, car sharing is built around much shorter rental periods and a much higher number of rental cycles per vehicle. That increases the number of operational events during the day — vehicle access, check-in and check-out, condition checks, cleaning, issue identification and maintenance response.
Second, the fleet is distributed rather than concentrated around traditional rental locations. Customers can start and end rentals in different places, so you have to manage the geographic distribution of the fleet as well as the total number of vehicles.
That creates an additional planning problem. You need to understand demand by area, monitor where vehicles are actually located, identify areas where demand is likely to increase and reposition vehicles in advance.
I've already worked with some of these principles at MEGA, although I understand that Zipcar has its own systems and operating processes.