One thing about riding a recumbent bike that is a fact - seeing behind you is a challenge. You cannot duck your head and see under your shoulder. Using a rear view mirror - or better two - just like in a car is essential.
Now - a great product has hit the scene - to be available in Summer 2010 according to the website - that looks very promising.
I highly recommend checking this out. If it works, it will be great and I will be buying one. In my next post I will delve a bit deeper into the importance of the rearview when riding a recumbent bike and plan on mocking up a few images of my rides with what I see now versus what I could possibly see with the Cerevellum.