A Complete Guide: Crash Testing For Automobile

Road accidents are the major cause of death worldwide, even after strict rules and heavy fines and safety-driven cars.

• Worldwide, approximately 1.35 million people die in road crashes each year, on average 3,700 people lose their lives every day on the roads.

• In the USA, more than 38,000 people die every year in crashes An additional 4.4 million are injured seriously enough to require medical attention.

• According to the road ministry’s 2018 report, India had 467,044 reported road accidents. 60% of these accidents occur on the highway because of speeding.

• The current speed limit in India is 80 km per hour on a 4-lane highway, 70 km per hour for urban roads. State and local governments in India may, however, fix lower speed limits.

• In Japan, it is 100 km/ hour on the highway, 60 km/ hour on urban and rural roads.

• In the USA, The standard speed limit is 70 mph for rural freeways, a 45 mph minimum speed limit, 65 mph for other 4 lane divided highways, and 55 mph for all other highways.

WHO recommends limiting the speed to 55-57 km/ hour to curtail about 30-37% lives. Not surprisingly enough, this is the exact range that Crash Test organizations use to check the safety of the car.

The Ministry of Road Transport in India had mandated that all four-wheelers will have to be mandatorily equipped with airbags, seat-belt reminders, reverse parking sensors, and a manual override for the central locking system. ABS was standardized across cars, already.

All these measures are made to avoid a crash. But what happens to the occupants when it happens? What are the chances of survival? How do we predict serious injuries? What kind of impact is fatal? How safe is that vehicle in real-world scenarios?

Crash Testing answers all these questions and more.

What is a Crash Test?

In an ideal world scenario, we would want zero crashes and zero fatalities. But let’s talk about surviving the crash:

It is all about Kinetic Energy. In plain physics:

K.E. = ½ m *v *v
K.E. ∝ V2
K.E. ∝ M

Even though M is constant, you can understand that as the speed progresses, the kinetic energy is increased exponentially. Even though the crash depends on several factors such as the angle of impact, the object of the impact, seatbelt condition, crumpling capacity of the car. The idea of a perfect crash is to utilize that kinetic energy until it becomes zero.

A. car safety system performs the following steps:

a. Seatbelt pre-tensioners tighten up the seatbelts soon after your car impacts, but before the airbag deploys.

b. The airbag is deployed

c. Force limiter releases the seatbelt after receiving the signal from SRS signal assembly

That’s why we need a crash test to understand how kinetic energy is behaving and impacting the vehicle and its occupants.

B. Crash Test Entails These Things:

1. Type of crash test (Frontal/ Rear/ Side etc.)
2. Crash Test Dummies
3. Crash Test ratings

1. Types of Crash Testing

• Frontal-impact tests: The vehicle is impacted at a straight wall at a specific speed.

• Moderate Overlap tests: The car impacts with a barrier. That is to say when a smaller fraction of the car is required to absorb all of the force.

• Small Overlap tests: A small portion of the car’s structure strikes an object such as a pole or a tree, or if a car were to clip another car.

• Side-impact tests: The car is impacted from the sides with a barrier. Side airbags come are the saviors in this scenario.
• Pole-impact tests: A pole impacts at a smaller portion of the car. Similar to Small overlap tests, a large amount of force is applied to a small proportion.
• Roll-over tests: It checks the car’s roof structure strength to support itself in a dynamic impact.
• Roadside hardware crash tests: These tests are done to ensure that guard rails, signposts, light poles, and similar appurtenances do not pose an undue hazard to vehicle occupants.
• Old versus new: An old and big car against a small and new car, or two different generations of the same car model.
• Computer model: Simulated crash tests using computer models to refine their vehicle or barrier designs before conducting live tests.
• Sled testing: It is used to test components such as airbags and seat belts by using reverse-firing sleds that are fired from a standstill, and decelerating sleds which are accelerated from a starting point.
• Head restraints & seat test: IIHS tests vehicle seats and head restraints with a crash test dummy that has a realistic spine.
• Headlight evaluation: IIHS does it where engineers measure the reach of a vehicle’s headlights as the vehicle travels straight and on curves.

2. Crash Test Dummies

A crash test dummy is built from materials that mimic the physiology of the human body, coming in different sizes for males, females, and children.

The real job of a dummy is to get the findings which are not possible to find from a real damaged human body.

It has 3 kinds of equipment to gather data:

• Accelerometers: These devices measure the acceleration in a particular direction. It is used to check the probability of the injury and the sight of the injury.
• Load sensors: They measure the amount of force on different body parts during a crash.
• Motion sensors: Placed in dummy’s chest, they measure how much the chest deflects during a crash.

3. Crash Test Ratings

There is a lot of research that went to define the injuries so that the safety of the car could be rated. The car is basically rated in three scenarios based out of 1-5:

-Frontal Crash

It is given for the driver and side passenger, separately, based on the injuries to the below parameters.

• Head Injury Criteria (HIC)
• Chest deceleration
• Femur load

10% or lower chance of serious injury reflects a 5-star rating.

46% or greater chance of serious injury reflects a 1-star rating.

-Side Crash

Side impact affects the following parameters.

• Thoracic Trauma Index (TTI)
• Lateral Pelvic Acceleration (LPA)

10% or lower chance of serious injury reflects a 5-star rating.

26% or greater chance of serious injury reflects a 1-star rating.

Organizations

Most of the car manufacturers use different quality materials for the same model in a different country. It becomes all-the-more important that every country has its own standardized assessment program.

A New Car Assessment Program is a government car safety program tasked with evaluating new automobile designs for performance against various safety threats.

1. U.S. NCAP – United States New Car Assessment Program
2. IIHS – Insurance Institute for Highway Safety
3. ANCAP – Australasian New Car Assessment Program
4. JNCAP – Japan New Car Assessment Program
5. Euro NCAP – European New Car Assessment Program
6. KNCAP – Korean New Car Assessment Program
7. C-NCAP – China – New Car Assessment Program
8. Latin NCAP – Latin New Car Assessment Program
9. ASEAN NCAP – New Car Assessment Program for Southeast Asia
10. Global NCAP – Global New Car Assessment Program
11. BNVSAP – Bharat New Vehicle Safety Assessment Program

Conclusion

According to Japan Road Safety report, the number of traffic deaths per 100 000 inhabitants in Japan has fallen by 57% between 2000 and 2017. In 2017, 3.5 traffic deaths per 100 000 inhabitants were recorded compared to 13.4 in 2000.

Coming from a place where accidents meant a disability or fatality, we have come a long way.

From figuring out the crumple zone in 1971 to finding side curtain airbags in 98′, and advanced frontal airbags in 2004, the vehicles are now safer than ever.

All credit goes to the national/ global assessment program’s (NCAP) rating systems and car manufacturers who put their heart and soul to make those vehicles luxurious, powerful, elegant but most importantly: SAFE.

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