warp - Has Star fleet improved interstellar travel?

The Federation has improved on warp travel over the years within the canon. Initially, warp travel required acceleration through the various warp levels, and the original Enterprise was limited to something like Warp 4 or 5. Her initial refit probably improved on that a little. Excelsior was commissioned primarily as a prototype and testbed for "transwarp drive", which both allows a higher maximum warp speed and the ability to instantly attain that speed from a standstill. This trans-warp drive eventually became standard issue, and the "trans" was dropped. The new technology also resulted in the recalibration of the Warp scale as speeds beyond the old Warp 9 were now not only possible but frankly easy to attain. The new Warp 9 is the start of an asymptotic rise in energy costs of warp travel up to infinity at Warp 10. Enterprise's warp drive maxes out at about 9.6, while Voyager's top speed is stated to be about 9.975. However, there are plenty of other "trans-warp" technologies that, without the energy costs of the Alcubierre-type Warp drive, can produce speeds in excess of Warp factor 9.9999.

Beyond the events of Nemesis and Voyager, one would think that the technologies documented by Voyager would result in some pretty big strides made in Federation interstellar travel. Slipstream in particular; they were able to bring home a (burnt-out and no longer working) example of that technology that Federation scientists would be very eager to reproduce. But, as Voyager is the end of the official canon, we won't know until someone starts up "The Next Next Generation" with the Enterprise-F or -G.