Unless you know of a way to decrease the half-life of tritium, afraid not. You get X decays per second, and those decays are converted into photons by the phosphors, yielding X photons per second. I'm assuming it's pretty efficient since tritium is a beta source, and you can stop beta particles practically with tissue paper, so probably most particles are turning into photons.

Here's what appears to be the patent for this:
http://www.freepatentsonline.com/4889660.html

Sure, you could use it in conjunction with a reflector, but that just makes it be a reflector, it's not increasing the output. This is going to be not really even as bright as conventional glow-in-the-dark plastics just after you turn the lights out. Not sure what you mean about parking; this would certainly make it easy to find your bike in the dark, if that's what you mean, but it's not going to draw a driver's attention.