NEW YORK --- According to automakers, conflicting vehicle safety regulations governing everything from air bags to bumpers to lighting in the U.S. and Europe are hindering efforts to bring fuel-efficient European models to the U.S. quickly.

An Associated Press report asserts that European regulators, the U.S. National Highway Traffic Safety Administration, and the Insurance Institute for Highway Safety also have different crash tests in which they publicly rate vehicles.

Ford's promise to bring six small, fuel-efficient vehicles from Europe and start building them in North America in 2010 puts a new focus on the challenge of satisfying governments' varying requirements, AP reported.

Ford plans to save billions by designing products for global sales, boosting profits on small cars. But competing interests among automakers, governments and the insurance industry are hampering efforts to standardize safety requirements worldwide. The result: extra engineering to make different versions of vehicles for different markets, AP reported.

"Each party negotiating this has their own views about their own standards being better," Ronald Medford, senior associate administrator of vehicle safety at the National Highway Traffic Safety Administration, told AP. "But as long as we can show we're not lowering safety and we're lowering cost, we're all interested in that."

Some differences are significant, like the U.S. rule that requires protection for passengers not wearing seat belts. There is no European equivalent. Others are small, like the U.S. requirement that vehicles have side lights, which are optional in Europe, AP pointed out.

The ultra-compact Smart car was sold overseas for nine years, but before Daimler AG could bring it to the U.S., it had to make the car longer to meet U.S. crash standards, spokesman Ken Kettenbeil told AP.

Automakers know how to retrofit their vehicles but question the time and expense involved when the changes may not make those vehicles safer, Jim Vondale, director of Ford's safety office, told AP.

"It may involve changes to the structure, it may involve changes to material, but they result in not so many differences in the safety levels of the vehicles," he said.

Ford recently studied 43 regulations in Europe and the U.S. and found that just 11 were equivalent, Vondale said. Fourteen had major differences that would require significant changes. Asian countries' regulations, which are closer to European requirements than those in the U.S., add even more complexities.

Automakers also have to contend with the Arlington, Va.-based Insurance Institute for Highway Safety, which is funded by the insurance industry and runs its own closely watched set of crash tests.

Tests may look similar on the surface but contain crucial differences. The European frontal crash test uses a deformable barrier — made to mimic another car — that slams into 40 percent of the front of the vehicle. That challenges engineers to spread the energy from the crash across the rest of the car. The fixed barrier in the U.S. test absorbs no energy, causing a severe crash that evaluates the vehicle's overall strength, AP reported.

Adding to the complexity of the frontal test is that the U.S. and Europe put their crash test dummies in different seating positions, which can affect how the air bags should deploy, said IIHS President Adrian Lund.

These are summaries of those tests.

Frontal crash test:

* Europe: A deformable barrier that covers 40 percent of the front of the vehicle strikes the vehicle at 40 mph. Adult crash test dummies are belted.

* NHTSA: A rigid barrier that covers the entire front of the vehicle strikes the vehicle at 35 mph. Dummies are belted. A separate test at 25 mph rates performance for unbelted dummies. Adult dummies are used, but a dummy representing a small woman will be used starting in 2010.

* Insurance Institute: A deformable barrier that covers 40 percent of the front of the vehicle strikes the vehicle at 40 mph. Adult dummies are belted.

Side crash test:

* Europe: A deformable barrier representing a small car strikes the side of the vehicle at 30 mph.

* NHTSA: A deformable barrier representing a car strikes the side of the vehicle at 38.5 mph.

* Insurance Institute: A deformable barrier representing a truck or sport utility vehicle strikes the vehicle at 31 mph.

Child Restraint Test:

* Europe: Dummies representing 1 1/2- and 3-year-old children are placed in the rear seats of frontal and side crashes in the restraints recommended by the manufacturer.

* NHTSA: None.

* Insurance Institute: None.

Rollover test:

* Europe: None.

* NHTSA: Test predicts a vehicle's chances of rolling over by combining measurements and the results of a moving test.

* Insurance Institute: None.

Pole test:

* Europe: An optional test in which the car is propelled sideways into a pole at 18 mph.

* NHTSA: Pole tests will begin in 2010.

* Insurance Institute: None.

Bumper test:

* Europe: A series of tests that replicate hitting adult and child pedestrians at 25 mph.

* NHTSA: None.

* Insurance Institute: A series of tests at 6 and 3 mph measuring damage to the vehicle.