Taken from The New York Times:
In an effort to reduce lane-change accidents, some automakers are trying radar to eliminate blind spots that could conceal an adjacent vehicle.
For example: Ford’s Blind Spot Information System, or BLIS, which uses radar located in each rear-quarter panel to scan for objects between the rear bumper and the outside mirror. If an object is detected, a small warning light in the side-view mirror illuminates. Recently, I tried BLIS on the 2010 Ford Fusion Hybrid, on which it is a $1,595 option, and it worked well, picking upa vehicle in the blind spot. But there is the cheaper way to eliminate blind spots.
Long ago I found the idea in a 1995 paper done for S.A.E. International by George Platzer, an engineer from Rochester Hills, Mich. In that paper, “The Geometry of Automotive Rearview Mirrors — Why Blind Zones Exist and Strategies to Overcome Them,” he described the problem and a far cheaper method to eliminate the blind spot.
Here’s the short and less technical version of what it says: The driver leans his head against the driver’s window and sets the mirror so that the side of the vehicle is just visible. Then, the driver leans to the middle of the vehicle(between the front seats) and does the same thing with the passenger-side mirror.
It is necessary to check that the mirrors are properly set, of course. Here’s how that is done: Watch a vehicle approach in the rear-view mirror. It should appear in the side-view mirror before it leaves the rear-view mirror. And then it should appear in the driver’s peripheral vision before it leaves the side-view mirror. When I Platzer-ized the Fusion Hybrid, I could see the nose of a vehicle appear just as the BLIS warning light illuminated.
So, what is the point of a system like BLIS.? In an interview, Steve Kozak, Ford’s chief safety engineer, acknowledged that side mirrors can be set to eliminate theblind zone. But most drivers don’t adjust their mirrors that way so BLIS is a valuable safety aid, he said.
“If we could train everyone in the United States to do it that way, then I think we would probably be a lot better and we wouldn’t need a system like this,” he said.