A group of consumer advocates sued the U.S. Department of Transportation on Wednesday for repeatedly delaying a potentially life-saving rule requiring backup cameras in new cars sold in the United States.

The rule, originally expected in 2011, would have prevented hundreds of deaths and thousands of injuries from “backover” crashes, when a pedestrian or a cyclist is struck by a vehicle moving in reverse, the groups said in a court filing.

A 2008 law signed by President George W. Bush directed the DOT to revamp rear visibility standards by February 2011. But the DOT pushed back the deadline several times and now plans to issue a final rule by January 2015.

“Assuming DOT does not again delay the rule, the backover rule-making will have taken nearly seven years — more than twice as long as Congress envisioned for the rule-making — at a significant cost in human lives,” according to the lawsuit.

Separately, U.S. officials said on Tuesday they added rear view video systems to its list of recommended safety features, which has historically encouraged automakers and consumers to consider vehicles equipped with the technology.

“While adding this technology to our list of safety features is important, I remain committed to implementing the rear visibility rule as well,” U.S. Transportation Secretary Anthony Foxx said in a statement.

Backover accidents cause an average of 292 deaths and 18,000 injuries a year, according to a 2010 study conducted by the U.S. National Highway Traffic Safety Administration. About 44 percent of the deaths are children younger than five years old.

If installed in all new U.S. vehicles, backup cameras could save annually at least 95 lives and prevent more than 7,000 injuries, NHTSA said in the 2010 study.

Requiring these cameras would add between $58 and $203 to the vehicle’s price, or as much as $2.7 billion to equip a fleet of 16.6 million vehicles. The last time U.S. new light vehicle sales reached that level was in 2006.

The lawsuit against the DOT is brought by Public Citizen on behalf of a group that includes Greg Gulbransen, who lobbied for a change to DOT standards after he accidentally backed into his son Cameron, who died. The 2008 law is named after Cameron.

The other petitioners are Susan Auriemma, whose daughter Kate survived a similar accident, the nonprofits Consumers Union of United States and Kids And Cars, Inc, and Advocates for Highway and Auto Safety.