By David Kiley USA TODAY

DETROIT — Consumers, many now driving trucks with big blind spots that block the view behind them, are rushing the market for alarms that warn when they are backing close to something.

Drivers of minivans, pickups and sport-utility vehicles are backing into and killing an average 88 people a year, besides causing billions of dollars of property damage. That's out of an average 116 people a year killed — a third of them children — by any kind of vehicle backing up, says the Centers for Disease Control.

Backup alarms that beep inside a truck or car when it is backing close to something are becoming one of the hottest automotive products, either as a manufacturer's option or aftermarket addition.

Outside, the systems look like several buttons set into the bumper. Inside, they beep faster as the vehicle nears an obstruction.

Ford Motor has one of the most sophisticated systems. It uses signals from both sonar and radar sensors in the rear bumper to detect moving and stationary obstacles up to 20 feet behind the vehicle.

Ford figured 20% of buyers would take the option last year on its Lincoln Navigator full-size SUV. Instead, 80% did, so Ford made it standard on the '03 Navigator and is looking to expand the number of models that offer it.

That kind of demand has created additional problems:

• Drivers who have the alarms are developing false confidence. Automakers say most of the systems are designed to prevent backing into stationary obstacles, such as posts or other cars, and can't reliably detect children, pets or other moving objects.

"That's why we don't market our systems for safety, but rather as convenience, even though our new system sees moving objects," says Ford product design engineer Bob Kwiecinski.

Some automakers have begun using rear-view cameras to better detect unseen children and pets. Nissan's Infiniti Q45 sedan has an optional camera that shows what's behind the car on the navigation system's screen. Honda has a similar camera system standard on its Acura MDX SUV and charges $900 for it on the Honda Pilot SUV.

• Buyers are frustrated to learn there aren't enough systems to equip all models and that they have to pay as much as $1,000 when they can find the option.

"Interest starts to decline when the price exceeds $500," says Frank Forkin at consultant J.D. Power and Associates.

Automakers are diverting most of the alarms to luxury models because buyers of those crave new gadgets and can afford to pay extra for them. But buyers of lower-price vans and SUVs are most likely to want the devices.

"We are seeing huge demand for our system, mostly among SUV buyers," says Lexus spokeswoman Nancy Hubbell, who says the company hasn't decided when to offer it on SUVs. Only the $55,000-plus, top-end Lexus LS430 sedan offers an alarm, and 61% of buyers get the device, twice what was expected.

Independent accessory companies are trying to fill the gap. Rostra Precision Controls, for instance, sells a $400 microwave-based system that detects stationary and moving objects up to 12 feet behind a vehicle. The company sold 5,000 units, mostly through car dealers, last year and says sales will climb to 10,000 units this year. More than 80% are bought for SUVs and minivans.

No government standards apply to backup warning systems. They are legal to sell even if they don't work as expected. The National Highway Traffic Safety Administration is studying systems that help vehicles avoid colliding on the highway, but those don't include backup alarms.

Insurance companies say they are keen to minimize backup damage, especially on SUVs, which can cost up to twice as much to repair as cars do after 5-mile-an-hour impacts. But so far, the big insurers, including State Farm, Allstate and Farmers Insurance, aren't offering discounts for vehicles with backup alarms, as they do for vehicles with anti-lock brakes and anti-theft systems.