The last bus of the night on any route is bound to see depressed ridership, regardless of when that bus runs. This is, quite sensibly, because there is no safety net if something goes wrong. Passengers have no ability to simply "take the next one" if they arrive at the bus stop late, miss a transfer, or simply lose track of time. There's no way to completely eliminate this problem, short of running 24-hour service (hmm... not a bad idea...), but it seems to me that we could at least make things better with a few operational simplifications.
As anyone who has ever used the system before knows, RTA has a few major trunk routes (1, 15, 16) that run on something approaching a reasonable frequency- 20, 40 and 30 minutes on weekdays, respectively, although 15 drops to an appalling 70-80 minutes on weekends. It also has two other types of routes: CommuterLink express routes, that run a few precious times per day, mostly during commute hours on weekdays, and the more ordinary local buses, which run roughly once an hour through much of the service area. Generally, these also shut down earlier than the trunk routes, although 22 runs surprisingly late on weekdays.
One of the troubles of taking transit is the fear of missing a transfer-- and this fear is compounded if the bus you're transferring to is the last run of the night. Sure, if everything goes right transit would work for your trip, but missing that last bus just once means an expensive cab ride, calling friends and family members for a lift, or a very long walk. And it's a fact of life that buses do run late, for whatever reason. Most of the time, they're not extremely late, but sometimes 5 or 10 minutes is enough.
So here's my proposal: The last bus of the night on each route should hold at major transfer points (Downtown terminal, Tyler mall, Moreno Valley mall) for connections from each of the trunk routes. That is, if the last #13 leaves downtown at 7:30, it should wait for the eastbound #1 at 7:15, the westbound #1 at 7:00, the eastbound #15 at 7:25, the eastbound #16 at 7:08 and the westbound #16 at 7:14. Under normal conditions, the bus would leave on time, but if any of these buses were so late as to not arrive by 7:30, it would wait until that bus arrived. Most importantly, RTA should publish this fact in the Ride Guide, providing riders with confidence that they will not miss their connections.
Would this have the effect of making the last bus of the night run light? Probably. But it's a lot better that the last bus of the night runs late than that it runs early. Is this a lot to keep track of? It sounds like it, but RTA has automated bus-tracking capability. They could likely write a computer program to do this, and alert dispatchers when holding a bus is necessary. Would this drive a little overtime? Probably, but I doubt it would drive much. Evening buses are usually on time, thanks to lighter traffic. What it would do, however, is make those last buses of the night somewhat more attractive to riders, as they could count on making their connections-- and it would likely do so at a reasonably minimal cost.