Ignorance is no longer BLIS
We hate to admit it, but our one true driving weakness is the blind-spot. So yeah, when you see the Engadget-mobile cruisin' around Manhattan, you should definitely get out of the driver's black hole, at least until we pick up one of the new Volvos with BLIS (Blind Spot Information System). The system is comprised of a digital camera that fires off 25 times per second; if the system believes a car has entered the blind spot, a visual indicator is signaled to the driver. But if you're in fog, heavy rain, snow, or any other condition with limited visibility, the system won't exactly, um, work—like any person, really. Especially us.






















http://www.off-road.com/products/new/new-shmirror.htm
I have something similar for my van (the ones I have are little bubble mirrors stuck on my regular side view mirrors), and they work great for navigating Manhattan traffic.
Might be cheaper, too.
Or you could, you know, adjust your mirrors properly:
http://www.cartalk.com/content/features/mirrors/
I tried these instructions, and they work fine for me.