This yields some interesting figures:
GTA runs 11 routes through an average of 22 trips, 6 days a week. That's 264 trips per operating day, and, adjusting for non-operating holidays, about 81,000 trips a year.
Average GTA loop length (out and back) is 17 miles, so trip length (out or back) is 8.5 mi.
A million passenger-boardings spread through 81,000 trips is 12 passengers per trip. Average (nationwide) city bus passenger trip length is 2.2 miles, and if Greenville passengers are similar, a GTA bus, at a given moment, has an average of about 3 riders. That number also passes a gut check - it is reasonably similar to what I observe when in Greenville.
At the same time, a million passenger-boardings yields about 1600 round-trips per operating day. Assuming most trips are round trips and that one-way passengers and more-than-one-round-trip-per-day passengers roughly balance each other out (I'm guessing, but that seems plausible), GTA serves about 1600 individuals a day. If the average "regular" GTA rider makes 2-3 trips a week, there are something like 2400 to 3600 regular users of the system. That also seems plausible. By way of comparison, Jesse Jackson townhomes has about 800 residents.
GTA's impact on traffic and the environment is likely to be, at this point, about zero. Given American city car trips carry an average of 1.4 passengers, we could suppose we were keeping about 1100 cars of the road per day, which is insignificant to traffic when reduced by the number of car-trip-equivalents the bus system itself adds to the road. Environmentally, it is also a wash: city bus fuel efficiency is about a third average city car efficiency (4-6 mpg vs. 15-17 mpg). Given ridership is only a little more than double private-car ridership, GTA's environmental impact is likely to be a net negative compared to the same trips being taken in cars, but not big in relative terms.
The GTA's present purpose, therefore, is unsuprisingly twofold. First, it provides limited transportation options (and therefore limited shopping and employment options) to a few people who cannot afford to drive themselves, are unable to drive themselves, or are not allowed to drive themselves. It is, in other words, a positive element of Greenville's rather stingy benevolence to the poor and infirm. It probably makes something like 1500 to 3000 Greenvillians' lives more livable - and these riders, 2-4% of the city's population, are likely to be among our most elderly and otherwise needy. By comparison, 16% of the city lives in poverty.
Second, the GTA is a placeholder for a future, more useful, transit system.
A fare increase or an assessment, or both, are in order. $1 is substantially less than the national average for city bus fares, and our tax assessments in Greenville are similarly low.
Not even NYC pays for its buses through fares, so any suggestion that increasing services would solve the revenue problem is unlikely, though service increases might solve other problems.
One opportunity, and a simple experiment, would be an east-west shuttle extending from Clemson to Spartanburg as follows:
Clemson U to Easley via 123
Easley to Furman via 123, 124, and 25
Furman to Downtown Greenville via 276
Greenville to Bob Jones via 29
Bob Jones to GSP via 29 and 14
GSP to Spartanburg and Converse via 85 and 29
and, of course, back around again.
The point is to connect the best unserved users of public transportation - business travelers and students - to the primary desired points: downtowns and the airport. Every 45 minutes during the day would probably suffice.
The trip for college students on the western leg would be fairly long, but college students are more tolerant of trip-length. Business travelers would be getting to go point-to-point faster than any choice other than a private car. A combination of funding sources (universities, etc.) would be available to the GTA for the service.
Obviously, you'd charge a special fare, maybe $7. Make it part of GTA, and you'd change both its image, and Greenville for the better. At least, worth a try.