NEW YORK (CNN) - One thing many SUV buyers like about their vehicles is the increased visibility. They feel like they can see farther down the road over the roofs of other cars. But that long-distance line of sight comes at a price that can be tragic.What SUV drivers can't see is what's close behind them and, when backing out of a driveway or parking spot, that could be a person. In many cases, it's a small child.More than 2,400 children are backed-up over every year in the United States. Of those, about 100 are killed. In most cases, those children are run over by a parent or other relative.Julie Peck's son, Jackson, was four years old when he was killed two days before Christmas. Jackson's grandmother couldn't see the young boy running up from behind just as she was backing up the family's SUV."He was gone instantly. They didn't hear a sound when the car backed over him," said Julie Peck. "When they pulled it off him, he wasn't making a sound."It's called the "bye-bye syndrome" said Janette Fennell, founder of the auto safety group Kids and Cars.Wanting one last chance to see mommy, daddy, or grandmother before they go, a child will run up behind the vehicle at the worst possible time. Small children don't realize that the driver may not be able to see them.While most drivers are aware that there are areas behind their vehicle in which they cannot see, many don't realize how large those areas can be. The problem is worse in trucks and SUVs than in other cars because of their increased height and the distance between the driver and the tailgate or rear window."More and more people are buying bigger and bigger," said Consumer Reports auto test director David Champion, "and the bigger the vehicle, the bigger the blind spot."Champion illustrated the problem using 28-inch-high cones, about the height of a typical two-year old. The cone had to be 10 feet, 10 inches from the back of a Subaru Impreza sedan before it became visible in the rear-view mirror.The cone had to be a little over 18 feet to be seen from the driver's seat of a Dodge Grand Caravan minivan and it was invisible up to 25 feet from the back of a large Toyota Tundra pick-up.From the driver's seat of a Chevrolet Suburban, a large SUV, the cone wasn't visible until it was 46 feet, nine inches away.For a shorter driver, the blind spots are even larger.Various factors, besides just the size of the vehicle, can affect the size blind spots. Small windows can make blind spots larger, for example, while high-mounted seats can make them smaller."On these big vehicles where we see something like 20, 30, 40 feet of blind spot behind, that is where the problems are," said Champion. "That is where the deaths we are seeing in backover accidents are occurring."It's a problem the industry isn't addressing right now, said Ron DeFore, a spokesperson for SUV Owners of America, an organization partially funded by car companies.There's not enough data, he said, to require automakers to come up with a solution.Optional equipment available on many trucks and SUVs can help solve this problem. Some cars and trucks are already available with sensors that sound an audible warning when something is close behind and the vehicle is in reverse. Some even have video cameras that show what's behind the vehicle where the mirrors can't see.For vehicles that don't have this type of equipment, several companies make products that you can easily install yourself.While back-up video camera systems can cost thousands of dollars, radar-based sensors cost much less, generally a couple of hundred dollars. Some of these systems take just a few minutes to install.Champion thinks systems like these should be required on all larger vehicles.But DeFore disagrees, citing the cost."If we take the attitude that any new technology, down the road, should just be mandated because it saved a few lives," he sad, "that is very dangerous public policy because you just start pricing vehicles well beyond what a lot of people can afford."Senators Hillary Clinton (D-New York) and John Sununu (R-New Hampshire) have proposed legislation requiring the U.S. Department of Transportation to issue regulations aimed at reducing accidents that frequently kill or injure children in cars.Feedback