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- Test Procedures and Evaluation Methods for Collision Safety Performance Tests (Front, Side and Rear)
Passenger cars are designed with a structure and the equipment to reduce the degree of injury to passengers in the event of a collision. The method of testing used to evaluate these features must ensure that collision simulated is as realistic as possible and that the data obtained from the tests is highly reliable.
In this test, dummies are placed in both the driver’s and rear passenger's seats and the vehicle is made to collide with a concrete barrier at a rate of 50 km/h. The dummies are checked for injuries to the head, neck, chest, abdomen and femur, the vehicle is checked for damage and deformation, and the results are used to evaluate the degree of passenger protection in 5 levels.
The dummy on driver's seat represented the average adult male until 2023 but it has been changed into one that simulates a small woman from 2024. The dummy on passenger's seat represented the small woman from 2018 to 2023 (the male until 2017) but it hasn't been mounted since 2024. The dummy on rear passenger's seat has represented the small woman newly since 2024. The test vehicle was made to collide head-on at a rate of 55 km/h until 2023 but the speed has been changed into 50 km/h since 2024.
This collision test has to simulate the accident at a rate of 50 km/h. Most of actual collisions occur at the speed lower than that of this test. Note that the results of this may not apply to collisions at extremely high speed, when occupants are not wearing seat belt or against a large truck.
Additionally, the results of collision tests may only be used for comparisons with test vehicles of approximately the same mass. This concept also applies to offset frontal collision test.
In this test, in addition to protection performance of test vehicle driver (Self protection: SP) which is evaluated from before, performance for reducing damage to the vehicle target (Partner Protection: PP) shall be evaluated as a new evaluation.
A test vehicle with dummies on the driver's and passenger's seat and a trolley with a mass of 1,200 kg are each driven 50 km/h in a head-on collison under the condition that a portion of the driver's side of the test vehicle (at an offset of 50%) is made to collide with the front of the trolley. The dummies are measured for injuries to the head, neck, chest, abdomen, pelvis (driver’s seat only), femur and legs (driver's seat only) and the vehicle is checked for damage and deformation, and the results are used to evaluate the degree of SP. Furthermore, the degree of PP is calculated to score based on deceleration of trolley, deformation value of barrier mounted on trolley etc. PP points are subtracted from SP points to get the total, which is then evaluated to one of 5 levels.
In new offset frontal collision test, PP as well as SP is an evaluation item, so it is required to secure PP to get a higher evaluation.
Among the passenger injuries which occur in automobile collisions, side collisions cause the most damage next to frontal collisions. In this test, a sled with a mass of 1,300kg(Until FY2017,mass of 950kg) is made to collide at a speed of 55 km/h with the side of a stationary test vehicle with a dummy normally on the driver’s seat. The dummy is checked for injuries to the head, chest, abdomen, and pelvis, and the results are used to evaluate the degree of passenger protection in 5 levels.
The front of the sled, which has been made to look like a normal passenger car, has also been outfitted with a shockabsorbent aluminum honeycomb which provides a similar degree of hardness as such a vehicle.
In addition, from 2008 to 2017, in case the test vehicle equipped with SCA (Side Curtain Airbag) situation and range of development of the SCA has been evaluated.
This test substitutes pole impact tests of which other NCAPs such as Euro NCAP has carried out.
* The side curtain air bag (SCA) has been designed to protect the head of passenger in a side collision, and is generally stored in a roof-rail, etc. In event of side collision, the bag blows open to expand mainly from A pillar to C pillar area along the roof-rail.
Rear-end collision occurs most commonly among the passenger injuries caused by automobile collisions and most of them are neck injury.
In this test, using a test device, rear-end collision shocks (velocity change (ΔV), wave shape, etc.) are given to dummies placed in the driver’s or front passenger’s seats. The degree of neck protection performance is judged on a scale in 5 levels based on the shock the neck suffered.
This test reproduces rear-end collision impact when a car crashes into a parked car which is the same in mass at a rate of around 36.4 km/h (velocity change (ΔV) of 20.0 km/h). Please note that evaluations in this test may be different from actual rearend collision accidents due to differences in collision speed, mass, passenger’s posture/physical size and seat’s adjustment position.
The test was conducted at the velocity change of 17.6 km/h from FY2009 to FY2011.
In this test, dummies are placed in the driver’s and rear passenger’s seats and the test vehicle is made to collide head-on on the driver’s side (at an offset of 40%) with an aluminum honeycomb at a rate of 64 km/h. The dummies are measured for injuries to the head, neck, chest, abdomen (rear passenger’s seat only) and legs, the vehicle is checked for damage and deformation, and the results are used to evaluate the degree of passenger protection in 5 levels.
While dummies had been placed in the driver’s and front passenger’s seats until FY2008, a male dummy placed in the front passenger’s seat was replaced with a female one and this female dummy was placed in the rear seat and “Rear Seat Passenger’s Protection for Frontal Collision Performance Evaluation” has been carried out since FY2009.
Because this test involves impact with only one part of the vehicle, the force exerted on the dummy is less than in a full-wrap frontal collision. However, while the full-wrap frontal collision test is well suited to evaluating restraining devices (such as air bags and seat belts)used to protect passengers, in this test there is a significant degree of deformation to the body of the vehicle, which makes it well suited to evaluating aggressiveness to passengers from such deformations.
Note that this test physically simulates offset frontal collision at a rate of 55 km/h similarly to full frontal collision test until FY2023. Most of actual collisions occur at the speed lower than that of this test.
Injury values are measured on the dummy for the head, neck, chest, abdomen (right or wrong binding of pelvis by a seat belt) and femur. These values are then converted into a four-point score using a pointconversion function. Steering deformation is also measured and converted in the same manner to a score of 0 to －1. The value for steering deformation is subtracted from the value for injuries, adjustment items are take into account, and then maltiplied by the weight coefficent based on the actual condition of the accident to caluculate the overall points of each body area. These scores are then added together to get the total, which is then evaluated to one of 5 levels.
Injury values are measured on the dummy for the head, neck, chest, abdomen and lumbar, femur and legs. These values are then converted into a four-point score using a pointconversion function. Steering deformation and brake pedal deformation are also measured and converted in the same manner to a score of 0 to －1. The value for steering deformation and brake pedal deformation are then subtracted from the value for injuries, adjustment items are take into account, and then maltiplied by the weight coefficent based on the actual condition of the accident to caluculate the overall points of each body area. These scores are then added together to get the total, which is then evaluated to one of 5 levels.
The total points (the maximum value:－5 points) are calculated by using pointconversion function based on OLC obtained from deceleration of MPDB trolley, SD obtained from deformation value of barrier mounted on trolley (the size of unevenness) and the existence of BO.
Injury values are measured on the dummy for the head, chest, abdomen and pelvis. These values are then converted into a four-point score using a pointconversion function used for automobile assessment in the United States and Europe. These values are multiplied by the weight coefficient for this type of accident and the overall points are calculated for each body area. These scores are then added together to get the total, which is then evaluated to one of 5 levels.
In order to evaluate injuries of dummy's neck, Neck Injury Criterion (NIC) as injury values to evaluate "neck's S-shaped deformation" which occurs head contacts to the head restraint (Phase 1) and neck load/moment as injury values to evaluate maximum headtilt after head contacts to the head restraint (Phase 2) are measured. These values are then converted into a four-point score using a point-conversion function used for automobile assessment in the United States and Europe. The result is multiplied by the weight coefficient for this type of accident. These scores are then added together to get the total, which is then evaluated to one of 4 levels.
For the driver's seat, the results of the full-wrap frontal collision test, offset frontal collision test, and side collision test are added together and evaluated to 6 different levels.
For the Frontal passenger's seat, the results of the full-wrap frontal collision test and the side collision test (results for the driver's or the front passenger's seat are used) are added together and evaluated to 6 different levels.
In full-wrap frontal collision test and side collision test, the score of each test for each seat, driver's seat or rear passenger's seat, is rated according to five levels. In new offset frontal collision test, the score calculated by subtracting evaluation points of aggressiveness to the opposing vehicle (Partner Protection: PP) from protection points of the test vehicle driver (SP: Self Protection) which is the total score for each seat, driver's seat or rear passenger's seat, is rated according to five levels.
In order to accurately differentiate between the evaluations of different vehicles, a standard is set based on current technology. In full-wrap frontal collision test and side collision test, up to 6 points out of 12 is given level 1 and the rest of the range is divided up into four equal parts, which are respectively assigned to level 2 (more than 6 points but 7.5 or less), level 3 (more than 7.5 points but 9 or less), level 4 (more than 9 points but 10.5 or less) or level 5 (more than 10.5 points). In new offset frontal collision, up to 12 points out of 24 is given level 1 and the rest of the range is divided up into four equal parts, which are respectively assigned to level 2 (more than 12 points but 15 or less), level 3 (more than 15 points but 18 or less), level 4 (more than 18 points but 21 or less) or level 5 (more than 21 points).
Four-color coding and points out of 12 are shown according to the driver's seat and front passenger's seat. Furthermore, in order to accurately differentiate between the evaluations of different vehicles, a standard of neck injury protection for rear-end collision performance is set based on current commercially-available vehicles. Orange represents up to 5 points out of 12 and the rest of the range is divided into three parts; yellow (more than 5 points but 8 or less), light green (more than 8 points but 10 or less) and green (more than 10 points).
Each color represents an estimated probability of serious neck injury at a residual disability level (WAD2+risk).
In this probability, a standard of neck injury protection performance for rear-end collision is set based on current commercially-available vehicles.
Orange (5 points or less) represents 89% or higher, yellow (more than 5 points but 8 or less) represents 66 to 89%, light green (more than 8 points but 10 or less) represents 44 to 66% and green (more than 10 points) represents 15 to 44%.
Please note that this injury probability is calculated on the basis of injury values when the Dealta V is 17.6km/h (reproduction of collision shocks when a car crushes into a parked car which is the same in mass at a rate of around 32km/h) and the passengers are seated normally and may be different from actual rear-end collision accidents due to differences in collision speed, mass, passenger's posture/physical size and seat's adjustment position.
※WAD: Whiplash Associated Disorders
From FY2008, the side curtain air bag deployment check was added to the side collision test.
