In Japan the National Organization for Automotive Safety & Victims' Aid (OSA), under the guidance of the Ministry of Transport, evaluates the safety performance of automobiles currently available in Japan.  The test vehicles are chosen from the country's best-selling cars, starting in model year 1996. 

In the full-width frontal impact test (adopted from the NHTSA full-width frontal impact tests), a moving vehicle with dummies in the driver's and front passenger seat rams into a concrete barrier at 55 km/h (35 mph), to evaluate the impact on the head and chest, and to check the condition of the deformed vehicle.

Side Impact Crash-Test Ratings Key (OSA rating):  Risk of Serious Injury to Head and Chest

	Very low risk (AAA)
	Low risk (AA)
	Moderate risk (A)
	High risk (B)
	High risk (C-D)

The current test results do not apply when occupants do not wear seat belts, the collision speed is very high, or a passenger car collides against a large truck, and collision occurs in the lateral direction. The results of the collision test can be compared with each other only when the compared vehicles are in the same weight class.  Thus,  you can estimate that an Acceptable vehicle is safer than a Marginal one when their weights are within 15% of each other.  But you should not assume tht an Acceptable vehicle weighing 1000kg is safer than a Marginal one weighing 1500kg.