Washington - The Obama administration is again delaying regulations already more than two years overdue on whether new cars and trucks must come equipped with rearview cameras to protect against drivers backing over people in blind spots behind their vehicles.

Transportation Secretary Ray LaHood said Thursday in letters to three members of Congress that more research is needed. He set a new deadline of January 2015 for the regulations.

An average of 228 people are killed and 17,000 injured each year because of back-over accidents. Many of the accidents occur in driveways and parking lots. Nearly half the deaths involve children under age 10.

The emotional toll of the accidents is especially high since many of the drivers are parents or family members of those killed and injured.

Congress passed a law in 2008 requiring the government to issue final regulations aiming at protecting against back-over accidents by Feb. 28, 2011, but the regulations have been delayed repeatedly. The law didn't require that cars and trucks come equipped with cameras in the rear of the vehicle that display images on a dashboard screen provided another solution could be found.

After studying the issue, the National Highway Traffic Safety Administration said cameras were the best solution and recommended more than two years ago that they be required on all new cars and trucks. The safety administration has estimated that making rear cameras standard on every car would add $58 to $88 to the price of vehicles already equipped with dashboard screens and $159 to $203 for those without them.