No cost car mirror solution exists
"Blind spot detectors" (on new, higher end cars), "magic mirrors". A free solution already exists if drivers simply adjust their side mirrors properly. Mistakenly, people set them so that the view from the normal sitting position has the inside edge view of each mirror just grazing the side of the vehicle. But you don't need to see the side of your vehicle; you need to see the traffic! Instead, position your head near the driver's window and then adjust that mirror so the inside edge view just grazes the side of the vehicle. Then for the passenger side, position your head near the center of the vehicle for adjusting the mirror. In this way you will be able to observe traffic moving from your rear view mirror, to your side mirror, to your peripheral vision, with no blind spot.
People initially find this new way unsettling because the side mirror view doesn't seem to be "anchored" to anything (the side of the car), but in practice this way produces a much safer, more complete picture for traffic awareness.
