Passengers tend to be packed more densely on
airplanes then they used to be in decades past.
So per passenger fuel efficiency per mile is actually quite good with aircraft.
And so you think of the kind of family maybe they take their trip in
the springtime from Michigan down to Florida and
often kids will talk about how they use to drive down.
And that's a money saving thing to do sometimes, but these days, it's
actually less fuel efficient to do that than it would be to get on an aircraft and
fly down there, because of the massive improvements in aircraft efficiency.
So, when it comes to long distance trips, it's surprising to most people,
but actually flying in an aircraft is the most fuel efficient way to get there,
not driving in your vehicle.
>> Wow. >> And there's safety implications
that come with that too.
>> Yeah, that's really interesting.
What are the safety implications associated?
>> Well with flying, flying is particularly safe.
We often have cases where we you have very bad news stories,
because there's large amounts of death and injury that occur all at once.
But over the course of a year, over the course of decades, flying is very safe.
Your main risk is when you take off and land.
When you're flying, you're generally doing fine.
But on that trip from Michigan to Florida, every mile has risk that comes with it.
Every time you have to get off the highway and
drive through cities, your risk goes up.
As I mentioned with hundreds of millions of drivers on the road, your
mixed in with all of those other vehicles on this multi-day trip to Florida.
So, there's a lot of different chances for there to be safety issues that come up.
Of course too driving by and large is very safe, but when you compare the two
side by side, flying is just a much safer way to travel than driving.
>> Yeah, that's really interesting.
And when you look at comparison between driving and an airplane,
it's interesting, because we always think of right before take off,
anyone that's ever flown on an airplane can look at that, and be like wow,
think about all of the green house gas emissions being created right here.
And it's really salient.
Is that something that you found in your work?
>> Well, as you mentioned, there's a massive amount,
you can even see it off and coming out of the engines of an aircraft.
But that's divided by whatever that, say, 250 people on that aircraft.
So as much as it's all coming out of a single aircraft, divided by the 150,
250, however many passengers there might be, the per passenger amount.
And if you were to then take those people and put them all into cars,
it actually ends up being more fuel efficient in the aircraft.
As much, as you say, sitting there doesn't feel that way,
because the aircraft itself is sort of cranking out so many emissions.
But it's carrying so many people and
it's carrying them so far, I mean actually it is a good trade-off.
And as you mentioned too, sitting there people often they're nervous and
they don't realize that around the world,
hundreds of people die every year in air travel accidents.
In the United States alone 30 to 40,000 people die on the roads every year.
So there's no comparison really [LAUGH] it's kind of apples and
oranges on the safety issues.
>> Let's dive a little bit deeper into the individual driver's behavior.
So, like many decisions that we make the individual
behavior that a driver has can have a really large
impact on the emissions that are coming out at the other end.
So for vehicles how much we drive, what we drive and how we drive,
those three items play pretty heavily into the carbon emissions side of things.
So, can you tell us a little bit more about those three categories?
And maybe provide a few examples from your research
about these specific actions individuals can take?
>> Sure, you mention these three sorts of categories,
we had a separate paper that preceded the paper we did addressing the Paris Accord,
where we looked at what we described as a strategic, tactical and
operational decisions that a driver can make.
And to put those in more sort of colloquial terms, strategic are more sort
of very long term kind of overarching decisions that you make.
Tactical are more of the things that may change from trip to trip,
depending on what you're doing, where you're going, things like that.
And operational, those tend to also be sort of overarching,
but they're more how you behave.
So for example, strategic decisions you might make are, the first one, of course,
is do you buy a car?
If so, do you buy a passenger car,
do you buy a pickup truck, some other form of vehicle?
Within those, pickup trucks,
you can improve your fuel economy by 100%, depending on the type you pick.
You could pick one with 15 miles per gallon, you could pick one with 30.
I believe with cars, once you get hybrids and electric vehicles in the mix, you can
do something like change your fuel economy by eight times the amount if you go from,
say, a very poor fuel efficient vehicle to one of the better electric vehicles.
You can have eight times the fuel efficiency there.
So, within even picking a car there's some massive range of effects you can get there
on those sort of strategic decisions.
Tactical is more, are you carrying any extra cargo or
loads in the vehicle that you don't need to be?
Are you taking the most direct route?
If possible, are you taking the flattest route?
Are you taking this trips at times when there's the least amount of congestion?
Of course, if you can take your trip at 2:30 versus 5:30,
I recommend doing it at 2:30 [LAUGH], things like that.
And then the operational decisions,
these are the things that you have to sort of think about on a more day to day basis.
It's doing things like avoiding aggressive driving, making sure your vehicle's
maintained, that you have proper inflation in your tires.
That you're actually using the oil that they say.
Things like using the incorrect oil though your car might run fine,
it actually can have some impacts on fuel economy.
So all of these little things that you have to make
decisions about every time you drive your car
sort of all add up to these operational decisions that you have to make.
And all of it, of course, can have some big impacts.
There's wide ranges of how much impact each thing can have.
But in an analysis we did, where we used some kind of reasonable amounts for
each of these different things,
you can almost cut your fuel economy in half if you do everything wrong [LAUGH].
We sort of started off with a model of fuel economy somewhere in the thirties,
and it cuts down to just a little under 20 MPG if you drive aggressively,
you drive fast.
Even using things like your air conditioning a quarter of the time can
cut your fuel economy by 3 or 4%.
So, there's all these little things.
And you may decide that 3 or 4% is reasonable for you,
because you want your air conditioning,
but that you'll make it up by not driving aggressively or things like that.
So, you can't necessarily add fuel economy, but
you can certainly hurt your fuel economy quite a bit by these long list of things
that you potentially fail to address or pay attention to as a driver.
And you can really have the reverse effect and keep your kind of maximum
fuel economy if you pay attention to these different things.
>> Yeah, sounds like one of the major takeaways from that second paper that you
discussed is that small incremental changes in driving behavior can
actually lead to really large greenhouse gas emission
reductions within the transportation sector.
>> Yeah, yeah and as I mentioned, a lot of that is because there's just so many of
us, almost every household in the US has at least one car, some have two or three.
