The Senate has passed a bill intended to help prevent deaths due to "backover" injuries. These are deaths that occur when drivers back over children they cannot see behind a vehicle. Under
the bill [PDF], which has already been approved by the House, the U.S. Department of Transportation will issue new safety standards that will require a rearward visibility performance standard for all vehicles.
KidsandCars.org provides lots of background on backovers and child safety.
Here is a Consumer Reports list detailing the best and worst rear blind zones.
The number of children who have died from backover incidents has increased dramatically in recent years. From 2002 to 2006, 474 children died from backovers, compared to 128 from 1997 to 2001. Half of all non-traffic fatalities involving children are reportedly due to backovers. The federal government does not collect data about non-traffic incidents, so the actual fatality numbers are likely much higher. Since 2000, more than 1,350 children have died in non-traffic
incidents, with at least 227 fatalities already in 2007, according to
KidsandCars.org.