Image Credit: Mark Elias/Bloomberg via Getty Images

Mandating rearview cameras in all passenger vehicles, would be the first government mandate designed to protect someone outside the car, but despite three letters from Transportation Secretary Ray LaHood notifying Congress it anticipated action by Wednesday and a prominent media report, ABC News has learned the Department of Transportation has decided to again delay what critics say is a life-saving measure.

"While the Department has made progress toward a final rule to improve rearward visibility, it has decided that further study and data analysis - including of a wider range of vehicles and drivers - is important to ensure the most protective and efficient rule possible," the Department of Transportation said in a statement. "The Department remains committed to improving rearview visibility for the nation's fleet and we expect to complete our work and issue a final rule by December 31, 2012."

This is the second delay by the DOT, a yearlong postponement in all that KidsandCars.org, a nonprofit organization that's mission is to improve the safety of motor vehicles for children, says could cost 100 additional deaths.

The surprisingly terrible statistics are that 50 children a week are backed over by a moving vehicle, resulting in two deaths, with the majority of fatalities being toddlers one to two years of age.

Sixty percent of these tragedies happen in larger vehicles, which have larger blind zones - the area behind the vehicle that cannot be seen. The blind spot for a pickup truck is 30 feet, while the average SUV or minivan has a blind zone of 15 feet and a family sedan has a blind zone 12 feet deep.

Fixing this problem would cost $200 a vehicle, $2.7 billion overall, according to Bloomberg. That is $18.5 million for every life saved, a cost-benefit ratio advocates say they hope is not too steep for government regulators.