Sorry to break it to you bud but that's not always good enough. I can remember plenty of times where looking over my shoulder simply wasn't enough. Fortunately, I've always been lucky enough to see the car in my blind spot just moments before I changed lanes, but not untill after I had already started makig the move. I kept telling myself to get one of those convex mirrors but never got around to it. One of the first things I did after I bought my new car just weeks ago was stop at walmart and pick up one of those cheap little 2" round convex mirrors you stick to your drivers sideview mirror. Probably the best $.98 I've ever spent.