Beauty has its price, one that can cost thousands of dollars in a car crash of 5 mph, according to the latest tests of bumper efficiency by the Insurance Institute for Highway Safety.

Newer cars with sleeker, flush-mounted front and rear bumpers may look good, but they do a poor job of standing up to the bump and grind of everyday life, the institute said.

The Arlington-based IIHS, which does safety and damage-claims research for the nation's biggest auto insurers, recently crashed seven large and luxury cars to determine whether their bumpers would prevent, or at least limit, vehicle body damage in low-speed collisions.

All seven failed, allowing total damage of at least $1,800 in a series of four different tests, the institute said.

Auto industry representatives dismissed the institute's findings as lab results that, as General Motors Corp.'s safety engineering director, Robert C. Lange, put it, "have no relevance to the real-world safety performance of vehicles." Officials say the trade-off of lighter bumpers is greater fuel efficiency and better overall safety in higher-speed crashes.

Much as it may surprise drivers, bumpers are not deemed to be personal safety devices by the National Highway Traffic Safety Administration. NHTSA has a "consumer standard," rather than a safety standard, relating to bumpers. That standard, which took effect in 1983, says front and rear bumpers must be able to withstand an impact of 2.5 mph without allowing vehicle body damage.

The 1983 rule replaced a 1973 standard that had set the damage-resistance level at 5 mph. Automakers argued that the old standard was in conflict with federal fuel-economy rules, because tougher, heavier bumpers added weight to cars. More weight generally results in higher fuel consumption.

Others in the auto industry argued that the 5-mph standard also ran afoul of NHTSA's attempts to make cars safer for pedestrians. Tougher bumpers protected car bodies but did more damage to human bodies in vehicle-pedestrian collisions, officials said.

"It's easy to do armchair engineering," said Gloria Bergquist, spokeswoman for the Washington-based Alliance of Automobile Manufacturers, which represents a coalition of domestic and foreign car companies on regulatory matters.

"We have thousands of engineers working on all sorts of things--safety, fuel efficiency, air bags," Bergquist said, adding that solving one problem sometimes means creating another.

The problem with many modern car bumpers, foreign and domestic, is that they are designed more for style than vehicle protection, said IIHS spokeswoman Julie Rochman.

"There is not enough room between the bumper and the car, which means there is no energy cushion between the bumper and the sheet metal. As a result, we're seeing some very expensive damage to sheet metal," Rochman said.

Consumers should be concerned, Rochman said, because much of that money comes out of their pockets in the form of insurance deductibles.

Two of the most expensive cars tested by the institute sustained the worst damage: the 2000 Cadillac Seville sedan, which retails for $44,000, and the 2000 Lexus GS 400, which sells for about $46,000.

The Seville received $2,735 worth of damage in two front and two rear collisions; the GS 400 sustained $2,746 in bodily injuries in the same tests, according to the institute's findings.

Among the large family cars, the 2000 Chrysler LHS sedan and the 2000 Chevrolet Impala sedan took the biggest hits to the wallet, with the Impala receiving $2,342 worth of damage and the LHS being knocked about to the tune of $2,406.

Consumers should not be alarmed by the institute's findings, GM officials said. For example, they pointed out, the Impala sedan that received thumbs-down in IIHS's bumper tests is the same car that received NHTSA's top, five-star safety rating in tests aimed at determining how well vehicles protect their occupants in frontal crashes of 35 mph.

Modern cars are designed to absorb crash energy on the outside to help prevent those forces from reaching the occupants, GM officials said.

EXPENSIVE BUMPS

Here is the total damage to bumpers in four tests* conducted by the Insurance Institute for Highway Safety (at 5-mph impacts):

Buick Park Avenue

1999-2000: $1,806

Cadillac Seville

2000: 2,735

1997: 1,958

Lexus GS 400

1998-2000: 2,746

Buick LeSabre

2000: 2,084

Dodge Intrepid

1999-2000: 2,115

Chevrolet Impala

2000: 2,342

Chrysler LHS

1999-2000: 2,406

*per vehicle

SOURCE: Insurance Institute for HIghway Safety