CARTA does not go to certain locations for lack of ridership, parking, or spaces to pull up buses. Smaller commuter buses (like the ones used by the VA) are a possibility, but targeted express routes could also be expanded. Routes could be strategically planned using information available from large employers.
For instance, MUSC parking has information on when employees scan in and scan out of the parking garages and have additional information on their address. This information can be used to calculate starting place of daily commutes and determine where areas of higher ridership for CARTA might be. MUSC and C of C have info-matics folks who can also do GIS analysis to help implement a strategy to encourage use of public transportation. Targeted surveys could then be sent out to employees in those areas (from the employer – again so as not to violate privacy agreements).
Of course, this would have to be done with an honest broker so that sensitive information would not leave the entity (the employer) and violate privacy agreements.