The success of carsharing clearly isn't just about how good the operator of the service is, it's also based on the overall balance and richness of the transportation environment of the city (and how the operator designs their service to fit into that environment. Figuring out some way to "rate" cities on mobility seems like a key to greater understanding for policy makers, as well as a way for the carsharing operator to understand the city they're serving better.
The author's, François-Joseph Van Audenhove, Laurent Dauby. Oleksii Korniichuk, Jérôme Pourbaix
have divided the mobility factors into Maturity and Performance categores, and include both carsharing and bike sharing in the Maturity ratings. (I wonder if they'd include Uber if they'd been writing the report in 2015?) These factors were weighted and the index score calculated.
Of course one can quibble. I would have substituted "smart PHONE penetration for "smart card penetration" and, ideally, some sort of land use rating to describe the proximity of neighborhood services that enable residents to not make trips at all.
While developing a index is can be useful, much can get lost in the process. I noticed that Lost Angeles scored slightly better than Portland (my home town) but it's hard for me to imagine that LA really has a "better" urban transport system?