A company I work for from time to time installed back-up monitors in their fleet of about 100,000 delivery vehicles in the US. The frequency of backing accidents actually increased after the cameras were installed. Nearly all of the post camera accidents were due to backing into something high off the ground (branches, gutters, eaves, telephone wires, etc.). Just something to keep in mind.
'04 GMC Sierra 2500HD, CCSB, D/A, MaxBrake, B&W Companion, Retrax Pro, AR Power Steps
2013 Rockwood 8289WS w/Diamond pkg
1969 Camaro RS/SS Convertible
Dad's old 1968 Empi Imp (recently recovered from under 21 years worth of boxes/dust)