Yes, though currently the interfaces to do this aren't yet official (i.e are subject to change)
Line 75: vtMain = new Franson.VehicleTrackerMain();
Insert: vtMain.vTracker.setUpdatePositionsInterval(2000); // (ms) update every 2s.
Line 11: g_buddyTrackerMain = new Franson.BuddyTrackerMain();
Keep in mind that the update intervals affect performance.
We're currently working on a settings/configuration interface intended to expose these kind of parameters to the user. Expect to see this in the near future.