The Science of Vehicle Safety

According to the National Highway Traffic Safety Administration,

>30,000
Fatal crashes occur
Each year

A whopping 19% of these crashes are most likely to occur on a Saturday.

The good news is that car manufacturers have done most of the hard work for you.

That's right - crash tests have been implemented in the automotive industry to assure customers of what is called "crashworthiness."

Crashworthiness

simply means that the design and mechanical structure of your vehicle is adequate to protect passengers upon sudden impact. Crashworthiness standards are used to assess safety in both aircrafts and vehicles.

But how do automotive manufacturers accurately and completely test the crashworthiness of a vehicle? The odds are that you are more than familiar with the ubiquitous crash test dummy. (And, no, we're not talking about the band from the 90s.)

The design was a 95th percentile adult male dummy

created by Sierra Engineering Company

in a contract with the United States Air Force. Initially, the crash test dummy was designed to test the crashworthiness of aircraft ejection seats on rocket sled tests.
By the time 1997 rolled around, GM had adopted crash test dummies as the industry standard to comply with government regulations related to airbag safety and vehicle impact.
However, the first barrier crash test was performed by GM decades earlier in 1934

Picture this:

You and your family happen to be out for a Saturday afternoon drive to run errands or go to a soccer game. A light drizzle begins to fall. Moments later, you glance up and realize that the car in front of you has slammed on their brakes. You quickly react by pumping your own brakes with a squeal of tires.

In a split second, the most important question on your mind is likely to be: Is my vehicle safe enough to save my life in an accident?

This may be a question you have put serious thought into before purchasing your current vehicle. Or, maybe you've taken the safety rating of your car for granted and have no idea whether or not your vehicle is equipped to protect you in a crash.

National Transportation Safety Board (1979)

In 1979, the National Transportation Safety Board made crash testing mainstream by testing and grading popular vehicle brands on their safety capabilities.

1984

In the decades to come, Mercedes-Benz continually improved upon their crash test technology, introducing their first digital crash test system in 1984. Mercedes-Benz engineers still use classic crash test protocol in combination with digital testing to this day.

1960 s

Throughout the 1960s, Mercedes-Benz continued to use their crash test procedure to establish reliable vehicle safety standards.

1995

Offset crash tests were adopted, impact crash tests became an industry standard in 2003.

The first crash test dummy was invented in 1949.
First Mercedes-Benz Crash Test Introduced (1959)

Luxury brand Mercedes-Benz was an early player in the crash test game, implementing their first crash test as early as 1959.

Within the crash test, a test vehicle was driven head-on toward a stationary object. This simulated crash allowed Mercedes-Benz researchers to better investigate how both vehicles and occupants could be impacted in a realistic crash.

Hybrid IIIs are best at gathering data on frontal impacts. Other types of dummies specialize in gathering data on other types of impacts:

Type of dummies used for impact tests

SID

(Side Impact Dummy)

Measures rib, spine, and internal organ shocks in side crashes.

BioRID

(Biofidelic Rear Impact Dummy)

Assesses whiplash trauma from rear collisions

THOR

Has a more humanlike spine and pelvis, its face contains many sensors too.

CRABI

(Child Restraint Air Bag Interaction)

A child dummy that tests child restraint devices.

Now that you understand how crash tests came about, it's time to answer the burning question on your mind...

A crash test is used to prove that a vehicle's design and safety features are effective on the road.

In essence, a crash test is intended to save your life and the lives of any passengers in your vehicle in the unfortunate event of a crash. To give you a better idea, a crash test may assess common vehicle safety features like:

Side Air Bags

Intended to protect the head, neck, chest, and pelvis in a side collision.

Frontal Air Bags

Intended to protect the head, neck, and chest in a crash.

Head Restraints

Intended to protect against head/neck crash injuries.

Safety Belt

Belt load limiter and pretensioner components are intended to absorb impact and restrain vehicle occupants.

Granted, a number of vehicles today are equipped with advanced crash avoidance technologies, like electronic stability control to keep a vehicle on the road and even a lane departure warning to alert a driver of accidental drifting. However, these safety features are in a separate category altogether of crash avoidance. Crash protection features, on the other hand, will be verified through crash test ratings to ensure that they hold up in minor to major accidents.

You can use the ratings earned from a simple crash test to determine exactly how a vehicle will hold up in an accident before investing your hard-earned money.

Of course, not all crash test results are created equal:

You can only use a model-to-model rating comparison in a frontal crash test within the same vehicle class or when comparing equal weight models (within roughly 250 pounds). Crash test ratings may not reflect how a certain model will perform in an accident with a larger or smaller vehicle.

Conversely, side impact crash test ratings can be used to compare vehicles in different classes since vehicle collision is tested with a sled at a consistent size and weight.

The reason that understanding crash test ratings is so important is because vehicle crashworthiness can fluctuate significantly from model to model.

To add yet another element into the mix, there are two different crash test agencies that perform frontal tests - often with different results. These agencies are:

The National Highway Traffic Safety Administration performs head-on frontal crash tests with collision into a solid obstacle. The drawback to this test is that the immobile object and crash angle hardly match real-life crash occurrences.

The National Highway Traffic Safety Administration performs head-on frontal crash tests with collision into a solid obstacle. The drawback to this test is that the immobile object and crash angle hardly match real-life crash occurrences.

You may find that NHTSA crash test scores have remarkably higher ratings since the crash test model may be lacking in authenticity. For this reason, the NHTSA recently updated their crash test ratings to implement the

More Stars. Safer Cars
program as of 2011

The new program includes:

A side crash pole test with newly designed.

Small-frame female crash test dummies.

Crash test scores are designed to be user-friendly and fairly easy to decipher. The NHTSA frontal crash test is categorized with 1-5 star ratings. The test scores can be broken down as follows:

>46% chance of injury.
36%-45% chance of injury.
21%-35% chance of injury.
11%-20% chance of injury.
<10% chance of injury.

On the other hand, the IIHS ranks crash tested vehicles in four separate categories, plain and simple:

Poor
Acceptable
Marginal
Good

Unlike the NHTSA government crash test, the IIHS doesn't break down crash test ratings by the potential risk of injury. The reason being is because IIHS crash tests evaluate a greater scope of the crash spectrum, beyond driver or passenger injury. IIHS crash tests take into account dummy movement/ejection, as well as vehicle design and structural performance.

NHTSA IIHS

Given the fact that there are two major crash test rating systems on the market, how do you decide which test results are more accurate?

Fortunately, the NHTSA and the IIHS support one another when it comes to vehicle safety standards. Both organizations believe that their crash test ratings can be used to complement the other and provide a clearer picture of overall vehicle safety performance.

Ratings gathered from both frontal crash tests will provide a better assessment of how a car will withstand an accident with a similar size and weight car or in a single-car crash. The crash tests do not measure vehicle performance and safety if a car were to crash into a significantly larger or smaller vehicle.

Here is a closer look at IIHS frontal crash test ratings for the 2013 Ford Escape:

2001-04
Models
2005-08
Models
2009-12
Models
2013
Models

Here are NHTSA frontal crash test ratings for the same vehicle:

**Tested with: Frontal air bag, knee air bag

Driver (male)
passenger (female)

Why are both agencies so front-focused when it comes to crash safety?

Believe it or not, most serious to fatal car accidents are single-vehicle collisions. Thorough frontal crash tests can be used to determine the potential risk of injury and overall performance of a vehicle in a common single-car accident or equal-car crash.

NHTSA

  • Conduct side-impact crash tests

  • Still uses a 1-5 star ratings system based on percentage of injury

  • The NHTSA is the sole organization to conduct rollover tests at this time

    (The NHTSA has opted to exclude rear crash testing since it is only associated with a slight percentage of fatal accidents}

  • The NHTSA does not conducts low-speed bumper tests

IIHS

  • Conduct side-impact crash tests

  • Rates vehicles with a Good to Poor rating

  • The IIHS is the only organization to conduct rear crash tests

  • The IIHS conducts low-speed bumper tests.

    (In general, low-speed bumper tests aren't directly related to injury and fatality risk in an accident, although they can give customers a better idea of how much average vehicle repair costs will be before purchasing)

Small Overlap Frontal Ratings

Good
Acceptable
Marginal
Poor
Dummy injury measures

Acura TL

Overrall
structure
Restraints & kinematics

Volvo s60

Overrall
structure
Restraints & kinematics

infiniti g

Overrall
structure
Restraints & kinematics

Acura TSX Sedan/Sport wagon

Overrall
structure
Restraints & kinematics

BMW 3 series

Overrall
structure
Restraints & kinematics

Lincoln MKZ

Overrall
structure
Restraints & kinematics

Volkswagen CC

Overrall
structure
Restraints & kinematics

Mercedes c-class

Overrall
structure
Restraints & kinematics

lexus is 250/350

Overrall
structure
Restraints & kinematics

audi a4

Overrall
structure
Restraints & kinematics

Lexus ES 350

Overrall
structure
Restraints & kinematics

Even with the many crash test innovations available in the industry today, it could be possible that your vehicle is not crash test rated.

Some vehicles may not be tested, or crash test results may be pending. Both the NHTSA and the IIHS primarily focus on popular vehicle models to meet public demand. For example, convertible cars may not be crash tested as frequently since they are less likely to be purchased by the average driver.

How Does a Crash Test Work?

Crash testing is a tough job, but somebody's got to do it.

Thanks to the continuous improvement of industry standards, crash testing is a highly extensive and thorough process, running up to $250,000 for a single vehicle prototype.

In the most popular type of crash test, A frontal test

a basic process is used that is not likely to vary by organization or manufacturer.

In a frontal crash test, a high-speed electric motor will pull a vehicle to a top speed of 30 to 60 mph at a distance of 500 to 600 feet.

The cost of the average crash test starts at

$100,000

Although the process sounds simple, crash test preparation is complex. It could take up to two days to create a prototype vehicle to meet such strict standards. The vehicle must also be fully equipped with testing sensors and mechanisms for safe fluid drainage. The undercarriage of the vehicle will be color-coded for video surveillance purposes; throughout the crash test, video cameras will capture the action at up to 1000 frames a second.

But the fun doesn't stop there - last but not least, a crash test dummy will be placed in a vehicle with its own unique sensors hooked up to monitoring devices. Dummy sensors to measure acceleration, load, and motion will be used to assess each aspect of a frontal collision to determine if a vehicle can perform up to its safety claims on the road.

A dummy's head and knees may be coated with grease paint to track where it comes into contact with the vehicle.

When conducting a standard frontal crash test in the United States, the Hybrid III dummy is used to ensure consistency. The Hybrid III dummy is created from materials that replicate the human body, complete with rubber pads and a spine made of alternating metal discs.

For further authenticity, Hybrid III dummies are manufactured in different height and weight percentiles and by gender. An average male crash test dummy may fall in the 50th percentile, meaning that it is medium-sized and equivalent to a 170 pound, 5'10" man.

No, a crash test wouldn't be complete without the presence of a crash test dummy. The dummy is used to sense how the impact of a real-life car accident would affect a human driver or passenger; data is then analyzed to determine an overall safety rating.

A well-rounded crash test assesses kinetic energy

Once a vehicle and dummy driver and/or passengers have come to a complete stop, energy absorption during impact will be evaluated. To dramatically lower the risk of injury, kinetic energy must be removed slowly and evenly in a crash. A vehicle is specially designed and equipped with safety features for this purpose, such as seat belts and airbags. A crash test can be used to determine if unique safety features are up to par before a car is road-ready.

The IIHS breaks down their frontal crash tests further into two separate categories:

Moderate Overlap

A vehicle will travel at 40 mph and crash into a deformable face barrier at roughly 2 feet tall. Within the vehicle, a Hybrid III crash test dummy of average male build will sit in the driver seat. 40% of the driver's side of the vehicle will be affected upon impact.

Small Overlap

Introduced in 2012, the small overlap frontal crash test will gauge the effect of a vehicle striking a smaller object, such as a pole or tree. The vehicle will travel at 40 mph and crash into a stable barrier at roughly 5 feet tall. A Hybrid III crash test dummy of average male build will sit in the driver seat. 25% of the driver's side of the vehicle will be affected upon impact.

Conclusion:
How Safe Is Your Car?

This brings us back to the evaluation of a crash test rating...
As a rule of thumb, it's recommended to choose a vehicle based on

higher front and side crash test ratings compared to other vehicles in its class.

So here we are again, back at square one: crashworthiness. In truth, the majority of vehicles on the road are far safer than they were years ago, dramatically cutting down on car accident fatalities.

Nonetheless, the vehicle that you choose does matter when it comes to you and your family's safety on the road. The next time you get behind the wheel to drive to the grocery store or take a cross-country road trip, you want to know that each and every person in your car is protected from danger in the event of a crash.

Since the NHTSA improved their star rating standards in 2011, it is difficult to rely on the same rating system for vehicles manufactured before that date. Many automotive industry experts instead advise leaning toward more stringent IIHS crash test ratings at either Good or Acceptable when considering a pre-2011 car.
The NHTSA website also provides a handy tool to compare safety ratings of different makes, models, and years of vehicles. This is especially helpful when comparing 2011 and newer models that have been tested with more rigorous 5-Star Safety Ratings.

Here is an NHTSA crash test rating comparison between the 2013 Honda Civic and the 2013 Honda Fit. As you can see, the four-door 2013 Honda Civic received the highest overall rating at 5 Stars:

Year | Make | model Overall frontal crash side crash rollover
2013 Honda Civic 2 DR FWD
2013 Honda Civic 4 DR FWD
2013 Honda Fit 5 HB FWD

If you're shopping for a newer vehicle based on crash test safety ratings, you're in luck. The International Institute for Highway Safety has upped the ante even further to create a newer, tougher crash test for the latest vehicle models, called

the Top Safety Pick "Plus."
The 2013 Honda Civic was the first compact car to earn the Top Safety Pick "Plus" award

Crash test results indicate that the 2013 Honda Civic scored Good on stricter small overlap frontal crash tests after colliding into a stable barrier at 40 mph with 25% of the front end. This new test was used in addition to standard IIHS crash tests.

Because of such stringent crash test standards, many vehicles have failed to pass. As a result, engineers must now implement more advanced car designs and modifications to ensure that newer models pass to earn acceptable safety ratings. The Center for Auto Safety confirms that the introduction of new testing standards is one step in the right direction to urge auto manufacturers to improve vehicle design and safety features.

If you're wondering what stands between you and a fatal car accident, it may all come down to top-notch safety engineering. Even a mere fender bender can cost you an arm and a leg in vehicle repair expenses. A more serious accident could cost you or a loved one your life.

It's no secret that car crashes remain the leading cause of death in the United States. Even worse, they are often entirely preventable.

You can increase your odds of successfully surviving a serious car accident by choosing the best car to crash in. Taking into account crash protection technology and crashworthiness determined by crash test safety ratings, some vehicle models will fare better than others in an accident, like:

Frontal Collision:
Chevy Cruze
Buick LaCrosse
Volvo XC60
Honda Odyssey
Toyota Tundra
Side Impact:
Chevy Cruze
Hyundai Sonata
Chevy Traverse
Toyota Sienna
Ford F150
Rear Collision:
Scion xB
Subaru Legacy
Ford Flex
Toyota Sienna
Toyota Tundra
Rollover:
Audi A4
BMW 5-Series
Volvo XC60
Honda Odyssey
GMC Sierra 1500
Taking the time to do your homework and review safety ratings before purchasing a new car could mean the difference between life and death in an accident.

Safety ratings don't necessarily reflect the price of a vehicle. Within the category of frontal collisions, a highly-rated compact car like the Chevy Cruze starts at $16,525 and is an IIHS Top Safety Pick. At the higher end of the spectrum, the Volvo XC60 starts at $32,400 and is also an IIHS Top Safety Pick for frontal collisions.

Crash test ratings are available for the vast majority of vehicles on the road today in a number of makes, models, and price points. If you do have to compromise on any features in your dream car, don't let safety be one of them. A car with a high safety rating and proven crash test results is truly priceles...

click here to embed this graphic on your website
share