- A few months ago, I crashed the old two-stroke dirt bike
during a motocross race, and as I was laying on my couch
recovering from said accident, I was thinking about
how my helmet and my pads probably saved my life,
but then I was thinking, well, when I'm in a car
I don't have a helmet and a pads on.
Heck, sometimes I don't even have a shirt on.
(wolf whistling)
What would happen to my body and my head
if I crashed a car instead of a bike?
Is there a trick to staying safe in a crash
when you're in a car?
So today we're going to look at exactly what happens
in car crashes and the things that we found
that can actually make some cars we have here
at Donut a little bit safer.
Let's go.
(groovy music)
So a car crash is the perfect place
to see physics in action.
Newton's three laws of motion dictate just about everything
that happens to your car and to your body in a crash.
- So the physics behind crashes is that an object
in motion stays in motion.
An object at rest stays at rest.
- This is Becky Muller, a senior researcher with the IIHS,
independent researcher working to test vehicle safety,
and what she's talking about is conservation of momentum
or Newton's first law.
So your body has got to be stopped by some force
and to determine how much force, we need to look
at Newton's second law which simply states
force equals mass times acceleration, and in a crash
that acceleration is actually deceleration of the car
from the speed it was going to a dead stop.
So the more massive your car is or the faster
you're going at impact, the more force the car is going
to impart on what it hits, which brings us
to Newton's third law, which states that for every action,
there's an equal and opposite reaction.
In the crash, that means that if you were to hit
a solid wall with 5,000 Newtons of force,
that wall is going to send 5,000 Newtons of force
back through your car.
So does that mean your body is getting hit
with all that force?
Well, if you were bolted to the front of the car,
like Mad Max style, heck yeah, you'd be freaking
getting all of that force, but mathematically,
sitting on the hood of your car would be the same
as being in the driver's seat in a totally rigid car
that didn't break or bend.
It's the same force, you're just placed
in a slightly different position.
So if we knew we had a totally rigid car,
we knew that the average car's around 4,000 pounds,
and we knew that bones break with only
4,000 Newtons of force, we'd be looking at broken arms
in a crash as slow as five miles per hour,
but luckily modern cars are not rigid.
They crumple up.
These crumple zones are designed to take that incoming force
and reduce the amount that makes it to you, the driver.
So how do you reduce force?
Well, if we look back at Newton's second law,
it shows us a pretty simple equation with only two things
that can ultimately reduce the force of impact.
You got mass, you get acceleration.
You can't really change the mass of your car mid-crash
unless you start throwing your momma out the car.
Hey ya, ho-ho!
(film beeping)
So let's look at the other variable in Newton's second law
and that's acceleration.
If we were to break down acceleration even further,
that becomes velocity over time, and it's this aspect
of time that we really want to focus on.
Since the crash happens so fast, this makes the deceleration
very, very high, but it also means that any small change
in time can affect the results of the impact.
This is where all safety equipment is geared toward,
making the crash take longer.
Those crumple zones, they're designed to slow
your rate of speed and bend with some resistance
but not enough to stay rigid and transfer force.
Seat belts, they're there to slow you down
before hitting your airbag which slows you down even more
before making contact with your steering wheel.
Hopefully you don't hit it though, because then.
(mimics squishing)
In a 30 mile per hour crash, a seatbelt decreases
the deceleration rate by seven times.
That's the difference between a bruised collarbone
and a concussion.
So rather than an impact being over in an instant
and therefore creating a super high acceleration,
it's dragged out for as long as possible to lower
the rate of deceleration, and if that impact goes
from a 10th of a second to only half a second,
that might not seem like that much, but that's a difference
between 10 G's and 50 G's hitting your body.
- It's packaging 101.
Imagine if you're shipping a fragile item.
You search out a really sturdy box.
Then you pack it with your packing peanuts
and seal it up with tape, and those kind of items
are like your seatbelt and your airbag system,
where we're cushioning the item inside,
the person inside of the crash.
Those are kind of your basic principles.
- So you've got a layer with some give,
that's your crumple zone.
You've got a rigid layer for structure.
That's your unibody or your cab, and you've got another
soft layer created by the airbag.
It's like a reverse s'more.
You got your cracker, you got your chocolate,
and you got your marshmallow, just flip those around.
(film beeping)
That's the physics of a crash.
So modern cars are designed to maximize the time taken
to come to a stop while keeping the passenger compartment
as unchanged as possible.
This means that the actual cabin is designed
to stay fairly rigid and prevent parts or the suspension
or steering system poking through the firewall
or underneath the floor pan.
You don't want that.
That's not good.
So is there a way that I can make my car safer?
What if I had a better seatbelt like a four point harness?
I'd be safer plus start living that JDM life.
- Yeah, I mean the manufacturer takes into account
all of the different aspects working together.
They don't just, you know, throw this airbag from the shelf
and this seatbelt from another shelf together
and put them in a car.
It's looking at the whole vehicle as a system,
and when you start fiddling with any one of
those components, it's unknown what effect that might have.
So the race car's the same way.
It's, it's tuned as a whole system,
both the five-point harness and the assumption
of the HANS device and the helmet and the roll cage
are all working as one giant system together.
- Okay, I'm not prepared to wear a helmet and a HANS device
every time I need to go to the store to get some
French toast ingredients, but what about
the outside of my car?
Can I make my crumple zones bigger with some bull bars
or some other aftermarket part?
- Things like putting those bull bars on the front of SUVs
or pickups may interfere or affect the sensors that are
in the front of the vehicle that detect
when a crash is happening.
So it may delay airbags from firing at the right time
or it may confuse the system about, you know,
what kind of crash are you in?
- An airbag takes only 30 milliseconds to deploy,
and if working properly, it can deploy some 50 milliseconds
after the initial impact.
That's fast, and it needs to be that fast
to catch your face just the right time.
If it's even less than a 10th of a second off
it can go from a life-saving device to a boxing glove,
but what I really want to know is what kind
of car is the safest.
If the time of the crash is the only thing
we can really control, wouldn't you want a big car
with a lot of room for crumple zones and air bags?
- Statistically, yes.
So in car-to-car crashes, if you're in
the bigger vehicle you win.
It's the laws of physics, but when in single vehicle crashes
whether it be a vehicle hitting a wall or a pole
or a vehicle rolling over, there are increased risks
with heavier, higher, bigger vehicles,
just because of that extra mass that's associated with them.
- Well, what about your own body?
If you're in a crash, what's the best thing you can do
in the moment to keep yourself safe?
Well, actually, it doesn't really matter.
There are so many different types of crashes
that you couldn't just rely on a reaction.
You'd actually have to perceive the situation
and make a decision and that takes a lot of time.
The average human reaction time is about a quarter
of a second, but that is based on either
an anticipated action or instinct.
Amount of time it takes your brain to process
and assess the situation, then act based on that info
is much, much longer, and it usually doesn't kick in
before your reactionary instinct.
Now in a crash, your body's going to react in that matter,
no matter what even if it's not the best move,
but what if we could stop those reactions?
Well, you might've heard the stories that a drunk driver
in a collision is more likely to survive
because their bodies are limp.
They don't react and tense up in a crash
and therefore they don't get hit as hard.
Now I am not saying at all the way to survive
a car crash is to be drunk.
In fact, drunk drivers are seven times more likely
to be involved in a fatal accident in the first place,
but even putting that statistic aside,
there have been dozens of studies done
to try and replicate this theory, and they've all shown
that there's no value to being drunk, and if you think
about the physics we've already gone over, that make sense.
Now I can't calculate how strong you are
'cause we've never met, but earlier we said
it takes 4,000 Newtons of force to break a bone,
specifically a typical human femur,
which is a pretty tough bone to break.
You know, I've broken a couple of femurs in my day.
You get around me, bam!
(laughing)
(film beeping)
Now, the reason I bring up your strength is because
you're not strong enough when you tense up,
real tense and tight, no matter how strong you are,
no matter how buff you are to break the bones in your body.
When you tense up your muscles, it's putting a force
on your bones, but it can't break your bones.
It's not 4,000 Newtons of pressure, right?
If we look at a 20 mile per hour crash into a wall
in a regular sedan, that's over 200,000 Newtons of force.
When those forces are that high, flexing is only going
to make less than 2% of a difference.
So if you're drunk and you're limp, that 2%,
that's not going to help you, and it's also definitely
not going to help you make a better reaction time
or make better decisions.
You've already decided to drink and drive.
That's the stupidest decision you could have made,
and even if you were perfectly sober,
you had a good reaction time and you anticipated the crash,
at 60 miles an hour, the car would have already gone 20 feet
before you could even react.
- A crash happens in 100 milliseconds
which is a blink of an eye, and so there's not a whole lot
that you can do once that crash has started
to really avoid or maneuver or anything like that.
- Becky and her team have done a lot of research,
and I mean, a lot of research into crash statistics
and casualties in the U.S.
There's one thing, though, that every scientist
wants in their data, and one thing that you can do
that will help you stay safer
in an unpredictable environment of a crash.
Be predictable.
If you're driving in a statistically average way,
the safety equipment is better optimized for your safety.
Now, let me, let me explain how this works, okay?
The IIHS test over 200 models every year and to test
each model, they need five cars to properly run each test
and it takes several months to do those tests.
For every variable you add to the test, you potentially need
to double the amount of testing time.
Let's say you wanted to run every test twice,
once with the seatbelt on and once with a seatbelt off,
but now what about with just a lap belt?
What about with just the chest?
What about with the chest belt under your arm?
What about your ultra plush seatbelt pad on your seatbelt?
It's not about how you're sitting or where
you're positioning your hands.
Even body types factor into crash safety.
- So we do use anthropomorphic testing devices,
more commonly known as the crash test dummies.
They come in all different shapes and sizes.
They definitely don't represent all aspects of humans,
and humans if you think about it vary greatly
in size and shape, so the test tool that we do have
is really great at being able to detect injury risks
for the general population.
- But you want to try to be as close to what the car
was designed for as possible.
The airbag is timed to catch the driver at the perfect point
assuming the deceleration of the body from the seatbelt
and things like side airbags and retractable pedals
are all designed assuming they know exactly
where your body is gonna be.
Things that put you outside of the normal parameters
of a test can put you at risk, things like seating position,
arm position, if your passenger puts their feet on the dash.
Catherine, this is for you.
I love you, sweetheart.
You've got to stop putting your feet on the dash.
You're going to blow your legs all the way back,
and then I'm going to have to be like,
"hey, this is Catherine.
"She's a human pretzel."
Even things like loose items in your car
can become projectiles with unknown consequences
in the event of a crash.
Now thanks to the data from these tests, OEMs have made cars
even safer but not everyone drives a brand new car
with the newest safety testing.
One of our writers here at B2B, Joey,
his car is 30 years old.
Well, you don't have to worry too much, 'cause there is
one thing that can absolutely help.
- So what am I going to be able to do?
I can't afford a new car.
Number one thing that you can do to help yourself
in any kind of crash is to wear your seatbelt,
to wear your seatbelt, seatbelt.
- What the (bleep)?
Okay, I'm going to be a straight shooter with you guys.
We honestly thought that we would find
a sexy answer to this question, some secret that nobody knew
that we would bring to the masses.
Well, as it turns out, the IIHS, the NHSTA and a bunch
of other organizations already found out
what that sexy answer is, and it's wearing your seatbelt.
- And there are still many crashes, especially in,
in the newest, good rated vehicles where I'm looking
through real-world crashes and I'm like,
"boy, that's a shame.
"That person wasn't wearing their seatbelt.
"They died.
"I guarantee that if they had been wearing their seatbelt,
"there are all these other examples of people
"that survived and walked away.
"Didn't just barely survive, but would,
"could have walked away without a scratch."
- It turns out the best way to survive a crash
was that thing right next to your shoulder all along,
freaking seat belts.
Staying in a normal driving position,
keeping your safety equipment unmodified,
and of course not being intoxicated
can all increase your chances of surviving a crash.
I want to thank Becky from the IIHS for sitting down
and talking with me.
She was really cool.
Thank you guys so much for watching B2B.
You want to see more kind of,
behind the scenes stuff of Donut?
We cut a lot of stuff out.
Well, sometimes we put that stuff on
what we call the Donut Underground.
There's a little button down there you can hit to join.
Until next week.
Bye for now.