- Why does driving a go-cart 40 miles an hour
feel way more exciting
than driving an SUV at the same speed?
Why is it that some slow cars feel faster than they are?
Well today we're going to look at the science behind
the sensation of speed,
what actually makes a car feel fast,
how your brain can trick you,
and why a slow-feeling car might actually be a good thing.
We did the math.
We did some real world testing
and now it's time to see how reliable
the old butt dyno can really be.
Let's go.
(upbeat music)
- Do you ever think, "Dang!
"I want to do some cool stuff,
"but I don't have the right hat."
Boom!
Problem solved.
Introducing the first official Kentucky Cobra Hat.
Perfect for doing anything in,
perfect for doing stuff like this.
(explosion booms)
Perfect for climbing ladders.
Perfect for shredding.
Perfect for chilling on the couch
with your boo.
She's in the bathroom.
I've been waiting so long for these to come out,
we've been working on 'em for a while
and I'm really, really, really stoked
on how they turned out.
High quality embroidery on the front,
that's the new official Kentucky Cobra Logo.
Donut hittin' the back, also embroidered,
meshed back, I love the fit, it's my new favorite hat.
I can't wait to see you guys wearing them.
Post pictures on Instagram, tag me in them,
I will repost.
That's how you're gonna look when you buy one.
- One of the main reasons that it's so difficult
to tell what speed you're going by feel
is that your body can't actually feel speed.
And you might be saying, "Oh, I can feel,
"I can feel speed Jer bear."
But you're not actually feeling speed,
you're feeling acceleration or g-force.
Acceleration is the rate at which speed changes.
So if you're holding a constant speed,
your acceleration is zero.
So if you were in a spaceship hurdling through space,
you wouldn't feel a thing, theoretically.
Now that's all easy to understand
but this is where it gets just a tiny bit trickier.
Acceleration is not a scalar measurement, it's a vector,
which means that to express acceleration
you need to have both a number and a direction.
Now if you want to go around a corner
at a constant 40 miles per hour,
the rate at which you're changing direction
affects the amount of g-force your body experiences,
and that is determined by the radius of the corner.
This is why pilots can train in a centrifuge.
A centrifuge mimics the forces the pilot would feel
by changing direction in a tighter circle at a slower speed.
So in a car what that means is any change in direction,
however small it is, results in an acceleration
and that sensation is what your body feels.
Now there are outside forces and variables
that make equations a lot more complicated
but there's also micro accelerations
that you might not even be aware of.
The bumps in the road, for instance,
will accelerate the car upwards
and then back down as it passes over the bump.
That accounts for the acceleration of the wheel
and every car would experience a pretty similar
micro acceleration at a given speed.
Where cars start to differ from each other however,
is everything else between the tire and your body.
The suspension, the chassis,
even the seat that you're sitting in can have an effect
on how much of that acceleration makes it to the driver,
how much your butt dyno can feel.
To approve this,
we're going to do a little field testing today.
We have an accelerometer app that's
going to measure g-forces and we have two cars,
we have a lowered FRS,
which is the epitome of slow car feeling fast,
and we have a Scion XB,
which isn't necessarily that much slower or faster,
but this will prove as our baseline car.
We're going to do the same run on the same street
with both cars, and we're going to look at the data
and see what it says.
And performing all of these tests
will be our field correspondent, Joey Rassool.
- You might remember me from my show, "Versus"
and if you do, I am sorry.
Here I'm just going to be testing, not hosting,
that's going to be Jeremiah's job.
- [Jeremiah] Neither of these cars are pulling huge gs
from speed but at normal road speeds,
the softer-sprung car generates less change in acceleration.
- So it's not about which car is faster,
we can always tell which car is faster.
This is about which car feels fast,
and I know that in this car I have accidentally gotten
to like 80 or 90 on the freeway
but because I didn't even think that I was going that fast.
And yes, like there is going to be a difference,
these cars have different zero to 60s,
the weight is different,
how it handles going up a hill is different.
But the point is that when these two cars are driving
at the same speed,
the accelerometer data is different.
Like right now I can see major changes in frequency,
I can feel the bumps.
- Now automotive manufacturers have a whole department
dedicated to these vibration.
It's called the NVH department
or noise, vibration and harshness, which coincidentally
is also the name of Nolan's new metal band.
(heavy metal music playing)
It's the NVH department's job
to eliminate rattles and shakes in the car,
but also define how the harmonics of a vehicle
might amplify vibrations.
So for the perfect consumer car,
the NVH department wants to build a car
that feels comfortable at any speed,
which means it's going to feel slower and more controllable.
But for a sports car,
they might tune up that sensation of speed
to give the driver that thrill of a quick car at any speed.
And this can be done in a couple of ways,
you can do it with a louder exhaust,
or piping in induction noises,
or simply putting an M badge on the back of it.
(crowd screaming)
Now as you look out of your windshield at the road,
you may think you know what speed you're going
but how much can you actually trust what your eyes
tellin' your brain?
A study published by Harvard shows just how wrong
your eyes can be.
So they did an experiment and the test took 30 people,
showed them 200 different videos
from a driver's seat perspective
and asked to estimate the speed the car was going.
The results were that the wider the video's
field of view was,
the more off the estimations of speed were.
The more context you have for where you are
and where the things around you are,
the slower you are going to think you're going.
Take a look at this video of a long hallway
and cover the center of it.
Immediately, the edges look like they are going faster
and that's because your brain has less time
to process the information
so it thinks the video is sped up.
Now when we cover the edges of the video
your brain can process that information quicker
so it feels like the video is played slower.
But peripheral vision isn't the only way
we can affect perception.
Many people say that lower cars feel faster.
In a 2004 study, the Transportation Research Board
set out to test that exact theory.
They found that when asked to drive a comfortable speed
in a simulator, drivers at a higher ride height
were consistently going faster.
Not only that, but 56% of the drivers thought
they were going faster in a lower ride height simulation
while actually going about four miles per hour slower
on average.
But vision is only one sense
that is giving your brain information on speed,
and we wanted to find out, if we took away your vision,
and we took away your ability to hear,
is your body able to tell any differences in speed?
Joey is going to drive me around
but I'm not going to have any auditory or visual senses.
I'm going to put these earplugs in,
I'm gonna put noise-canceling headphones on,
and I'm going to cover my eyes with this mask.
We're going to go for a little loop
here in Mulholland Drive, and Joey's going to tap me
and I'm going to have to tell him what speed we're going
to the best of my ability.
Let's see how good my butt dyno is.
Uh,
probably going 30.
- [Joey] 35.
- [Jeremiah] Uh,
35.
- [Joey] 44.
- [Jeremiah] Uh,
58.
- [Joey] 75.
- [Jeremiah] What?
- Uh,
42.
- [Joey] 45.
Still really close.
- Jeremiah] 62.
- [Joey] 69.
(indistinct)
- [Jeremiah] Uh,
58.
- 58, okay, there we go.
- So was I worse or better?
You were just more accurate overall,
which is really interesting.
So like my first thought is that this is closer
in drive characteristics to your F-150, it's--
- For sure. - A car for comfort,
the suspension's gonna like be, not similar,
but closer than the FRS.
And the FRS is just an unknown quantity--
- Right. - To your brain.
- Right. - You know?
- I will inherently know like, if you're shifting up or down
and then the revs go higher then I'm increasing speed.
- [Joey] Yeah so you're thinking about
acceleration and stuff.
- [Jeremiah] Right, so I think I'm like
trying to process too much information.
- All of the stuff that you're getting from the FRS
like, not knowing what speed you're going,
it doesn't matter if you're guessing higher or lower.
The fact that you're off--
- [Jeremiah] Right.
- Shows that like you're being overloaded by the data.
- Right.
So we can feel acceleration
and a car with stiff suspension can pass more acceleration
to our bodies.
Most of the acceleration doesn't feel like speed,
it feels like bumps,
but some of it can be misinterpreted by the brain.
These quick changes in acceleration are known as jerk.
And jerk might be responsible
for some of that sensation of speed.
And I say might 'cause everybody's past experience
can influence this feeling.
Some smaller events of acceleration and jerk
that your mind doesn't have context for can trick it.
That's jerk that comes from the vibration of the engine,
for example, or rumble in the exhaust.
Beginning race car drivers experience this all the time.
The body panics, the information is coming at you too fast
so you slow down to be able to cope.
The car can actually go faster, but you can't yet.
So to become a faster driver,
they practice reducing the sensation of speed,
and part of that comes from knowing the track
and knowing the car
so the driver's brain doesn't have to process
as much new information in the moment.
Well hold on, wait a second, hold on.
Wouldn't you want to panic?
Like wouldn't adrenaline help you go faster?
Let's imagine I give you a digital watch
that is flashing random numbers.
Now imagine if we sped up that watch right up to the point
that you can't read the numbers and it's just a blur,
right at the edge of what your brain and your eyes
can handle.
Then imagine I've pushed you off a building
with a bungee cord.
Well, that's exactly what some experimental scientists did
at Baylor (indistinct).
They had test subjects try and read the flashing numbers
as they were dropped from a bungee line.
And guess what?
They couldn't read any of the numbers.
It turns out that adrenaline doesn't make you act faster
in the moment, it does not increase the speed
at which your eyes and brain can handle information.
For a driver, the only way to slow down time
is to have less new information.
The more information you have from experience
or muscle memory,
the more brain power you can dedicate to the track.
But you can go too far.
A driver still needs information to know what's going on.
With no info,
your brain might be able to handle going faster
but it's not equipped to keep you on the track anymore,
and pretty soon you'll out drive the car.
So on a track, I'd rather be driving a slow communitive car
than a fast numb one.
But in road cars, we don't need all of that information,
we don't want to be bombarded with race car noises
and vibration.
So there are plenty of things that affect a car's feel,
and feeling fast might actually slow you down.
I think we've just accidentally proven that a loud exhaust,
cut springs and limo tint will make you less likely
to speed.
Thanks to my field correspondent Joey.
We're going to be using Joey a lot more
in our episodes of "Bumper 2 Bumper."
We're going to be branching out,
we're gonna be doing a lot more tests,
a lot more actual physical science.
So I hope that's what you guys like.
If you do, leave a comment,
hit me up on Instagram at @JeremiahBurton,
hit us up @Donut on Instagram @Donutmedia.
Till next week,
bye for now.