In what has been described as a long overdue move, the U.S. Transportation Department has issued a rule that will require rearview technology in all new cars and many light trucks.
The decision has been made in an effort to reduce deaths and serious injuries caused by backup accidents.
The final rule will require all new vehicles under 10,000lbs (22,000kg) and built beginning May 1, 2018, to meet the new rear-visibility standards.
The rule, issued by the National Highway Traffic Safety Administration (NHTSA), includes buses and trucks, but motorcycles and trailers are exempt.
The rearview cameras can be mounted on many different parts of the vehicle somewhere on the rear of the car.
They must give drivers a field of vision measuring at least 10 by 20 feet (3 to 7 metres) directly behind the vehicle.
The system must also meet other requirements including dashboard image size, lighting conditions and display time.
Backup accidents involving light vehicles cause an average of 210 deaths and 15,000 injuries a year, and victims often are children and the elderly, the U.S. government said.
Children under five years old account for 31 per cent of the deaths each year, while adults 70 years of age and older represent about 26 per cent.
NHTSA said the new rule, required in the Cameron Gulbransen Kids Transportation Safety Act, will save between 13 to 15 lives per year and prevent as many as 1,125 injuries annually.
The measure, signed into law in 2008, was named for a two-year-old Long Island boy whose pediatrician father backed over him in their driveway in 2002.
Although Congress passed the measure with strong bipartisan backing, delays in researching and writing the rules pushed the federal mandate past a number of deadlines.
Critics charged that the government was reluctant to put additional financial burdens on the auto industry already crippled by an economic downturn, even though some manufacturers had started to install rearview technologies like sensor systems.
In the U.S, 44 per cent of 2012 models came with rear cameras standard, and 27 per cent had them as options, according to the automotive research firm Edmunds.
'This day has been a long time coming, and we urge automakers to move quickly to beat the 2018 deadline,' said Ellen Bloom, senior director of federal policy at Consumers Union.
The government estimates that a rearview system will cost between $132 (£79) and $142 (£85) per vehicle.
For vehicles that already have a dashboard display screen, upgrading it to comply with the rule will cost less, about $43 (£26) each.
The technology will be phased in by manufacturers starting in May 2016, before it becomes mandatory two years later.
'Today's decision will save lives and save money for consumers,' said Jackie Gillan, president of Advocates for Highway and Auto Safety.
'Every make and model will be required to meet this new safety standard and every family will benefit.'
Researchers at the University of California, Irvine, started looking into the problem in the 1990s after noticing toddlers showing up in hospital databases of injured child pedestrians— many of them hurt or killed by vehicles backing out of home driveways.
In 1993, the NHTSA sponsored several studies that noted the disproportionate effect of backup accidents on child victims.
One report explored sensors and cameras as possible solutions, noting the accidents 'involve slow closing speeds and, thus, may be preventable.'
