Given the high possibility of back up accidents, and serious suits, if
property or bodily injury, a back up alarm can really ward off such problems
to a great extent. 
If one drives every day, and backs out every day in a typical neighborhood,
with 10 kids on the block. That could mean 30,000 times you have to back out 
from the driveway over 10 years. It could be 60,000 times if backing out of
the parking space to get back home is thrown in. In 60K back ups, the
likilihood of hiting a car, or person is very high. I have had no less then
4 such near misses myself. There were two actual hits and damages but a back
up alarm would not have helped. One was hitting a light post that was very
tricky, the pole was clearly a distance from my bumper but I didn't see the
pedestal it was sitting on, 1.5' high, and 3' in diameter. That pedestal had
a lot of bumper nicks on it. The second case was pure stupidity on my part, I 
tapped a parked van, but it was enough to wipe out my rear lights on the
corner. The point is, back up alarms are good to let anyone close to the rear
know a moving car is coming, and watch out. After middle age, it is not wasy
to completely swing around and look both ways. 
Garbage trucks use them, as the need to back up 100's of times a day. Why not
sedans too?
--- VFIDO 6.20.00 Gamma Candidate 1
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