“The main findings are that to make driving less energy intensive than flying, the fuel economy of the entire fleet of light-duty vehicles would have to improve from the current 21.5 mpg to at least 33.8 mpg, or vehicle load would have to increase from the current 1.38 persons to at least 2.3 persons.”
You can reject my argument but that just makes you wrong. Even the non-commute average load is still not enough to make the average long-distance trip more fuel efficient.
no significant headway
Also wrong.
“A new report from the University of Michigan’s Transportation Research Institute shows that flying has become 74% more efficient per passenger since 1970 while driving gained only 17% efficiency per passenger. In fact, the average plane trip has been more fuel efficient than the average car trip since as far back as 2000, according to their calculations.”
You need to recheck your math. It doesn’t make sense to divide the consumption by plane but multiply by car.
The math I used is an estimation, but a reasonable one. I didn’t divide by one and multiply by the other. I converted automobile MPG to MPG per passenger mile, by assuming various numbers of passengers.
If I burn a gallon of gas in a suburban, the suburban moves 27 miles. If I have 3 people on board, each moving 27 miles, the suburban has produces 81 passenger miles on a gallon of gas. That is 81 miles per gallon per passenger, or 81 passenger-miles per gallon.
If I put 3 more people on board, I produce 162 passenger miles on that same gallon of gas. The vehicle travels 27 miles, 6 passengers each travel 27 miles, passengers travel a total of 162 miles. One gallon of gas is burned. 162 passenger-miles per gallon, or mpg per person. The more people on board, the more efficiently the vehicle produces passenger-miles. (Obviously, the actual vehicle economy would fall slightly as I add weight, but the efficiency gains of carpooling would greatly exceed the negligible losses due to additional passenger weight)
I don’t know how many people were on the plane for the figures you provided. If I assume it was 200 people, then the plane’s economy is 67mpg/200, or 0.335mpg. If I assume 100 people, the plane’s economy is 0.67mpg. If I assume 67 people, the economy is 1mpg. All of these numbers are reasonable for jets capable of carrying a corresponding number of passengers.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
And I stand by my “no headway” claim, because I was careful to specify my meaning. There are viable options for transportation that do not rely on fossil fuels. Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today. The use of those vehicles is rising rapidly.
There are no commercially viable electric aircraft in the skies today, and no commercially viable alternatives to petroleum-based aviation fuel. Yes, the efficiency of those fossil fuels has increased, but no viable alternative is currently available, nor slated to be available in the near future.
The math I used is an estimation, but a reasonable one.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point despite it being a rare occurrence. If you compared apples to apples and calculated both based on the average passenger count, you wouldn’t get the same amount. The only way your point stands is if you only factor in trips that are greater than 200km with 3+ passengers - something that would account for 5% of all automotive usage and wouldn’t make a measurable difference in the total amount of emissions from cars.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
Except that no one was comparing airplanes to mass transit and, even if they were, this is not true unless you restrict it to a very, very narrow set of parameters. Buses can’t swim across oceans. Trains can’t either. There’s no practical alternative in many situations. My point, from the beginning, has been that there are other sectors who produce more emissions and are easier to fix than the emissions that airlines have. Unless we get those in-line first, there’s no point on focusing on aircraft and especially not in the context of going back to thinking like in the 1900s where people just don’t see their families.
Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today.
And are nowhere near prevalent enough to offset the emissions of cars in use today to make them emit less than airplanes or make them more fuel efficient than airplanes. Unless every ride has 3+ passengers, what you’re saying is simply not true.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point
As are you.
despite it being a rare occurrence.
There is no justification for your assumed average of 1.2 people per trip. You’re comparing “commutes” to things like “vacations”. I don’t take the wife and 4 kids with me to work; I do take them on vacation.
Even if we do assume a single rider, you don’t get to automatically assume “car”. An airplane is a mass-transit vehicle. A bus gives 180 to 300 MPG per passenger mile, and a train can be well over a thousand.
But we’re getting away from the point: whether by bus, car, train, plane, or even bicycle powered by a rider who consumes oxygen and expels CO2, the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip. We need to focus on reducing travel in general.
No, I’m not. Stop lying. I’m taking the average for both because that’s the only way to determine which is more fuel efficient and which sector has the most opportunity for a change.
You’re comparing “commutes”
No, I’m not. More lies. I used commutes initially because that was the most common usage for a car by a landslide which is the same thing I did for air travel. You weren’t ok with that so I used the more general number and took the total average for all types of rides in a car with any number of passengers at all distances. That number is 1.3 passengers per ride. Anything less than, taking a subsection of the rides to narrow it down to only rides with 3+ passengers and only for “vacations” or whatever other nonsense constraints you want to put on it, only reduces the total available impact since rides with 3+ passengers are already an extremely small percentage of rides in a car and “vacation travel” is an even smaller portion than that.
you don’t get to automatically assume “car”
I didn’t. You guys used the example of a suburban. Emissions figures separate out mass transit from personal travel because they’re not comparable and mass transit has less opportunity for impact since it’s already the most sustainable method of transportation.
the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip
A complete straw man. If people need to get to a destination, going on a shorter trip is meaningless as is eliminating the trip. The most impactful changes are those that have the highest ROI in terms of barriers and resources. Airplanes ain’t that.
So it makes sense to divide planes mpg by passenger but not car mpg by passenger? Because the 67mpg you’re quoting is per passenger.
A 4 passenger car that gets 20mpg, what’s the mpg per passenger? Two ways to get to the result: fuel used is divided between passengers so each passenger uses 25% of the fuel, so 20mpg/25% = 80mpg per passenger OR even simpler, 20 mpg x 4 passengers. The result is the same. For planes, using my example from another comment, 82mpg/passenger, 388 passengers, 82/388 = 0.21mpg/passenger with one passenger.
Don’t tell me you truly believe that planes consume 67mpg by themselves because then you’ll have to explain why they need to cary thousands of gallons of fuel… (13k gallons for a 777)
Again, you’re comparing the average number of passengers for all road trips vs the average number of passengers for all airline trips, but the purpose of both isn’t the same and just because someone took a plane to go somewhere doesn’t mean they won’t be taking their car to work. Compare both travels for the same purpose (in this discussion, vacations) and people don’t tend to go on vacation alone, that increases the number of passengers in the car, they don’t tend to go as far in their car so that also lowers the amount of fuel used for the vacation.
For all purposes of travel, planes are more efficient. The longer a plane trip is the more efficient it is because the plane loses weight as you travel, not the other way around.
How can you ignore the multiple sources I’ve provided to still get the math wrong? Flying is more fuel efficient than cars. The only way you can make it less efficient is to limit the car rides to only rides that have 3+ passengers and only those that are multiple hundreds of miles in distance. That limits the trips we’re talking about to such a small percentage of auto travel that making progress in that specific area renders it meaningless. The majority of the carbon impact of driving comes from all the other usage. Airline travel has been more efficient than road travel since the start of the millennium.
For all purposes of travel, planes are more efficient. The longer a plane trip is *the more efficient it is* because the plane loses weight as you travel, not the other way around.
The 67mpg/passenger number from the source I provided is based on trillions of miles traveled, don’t you think that’s taken into consideration?
I don’t get the math wrong, you interpret the data incorrectly and think that planes get 67mpg/vehicle instead of 67mpg/passenger and you compare car rides to work to long distance air travel instead of comparing leisure travel for both in which case cars are much more likely to be used for multi passenger travel.
No, I don’t. I’m arguing against your multiplication of the mpg of the Suburban because you arbitrarily picked 3 passengers. The 67mpg/passenger amount for planes is based on the average number of passengers in a plane. If we did what you’re doing and picked it based on ideal figures to suit our own points, the mpg for the plane would be even higher.
What was the average distance travelled by plane again? You keep dodging that part. If the plane is more efficient per passenger mile but people travel three to four times further when taking a plane for vacation vs a car then that means… oh my… plane vacations are less efficient because people use the fact that they travel quicker as a justification to go further away! 😱
Unless you think that the average American would travel 1900 miles by car (one way) for a one week vacation. Because if you think so then you’re truly hopeless.
Planes are more efficient the farther the distance traveled! The average commercial flight was 900km for 2022. Planes still only account for 5% of the total emissions when including commercial, private, and transport flights and accounting for emissions from contrails. Now do that math for cars, trucks, and ground transport. Go ahead.
people use the fact that they travel quicker as a justification to go further away!
They absolutely do not. People choose their destination first and then they determine the mode of transport. No one changes their destination to someplace farther away because it takes less time to get there by plane than it does by driving.
Unless you think that the average American would travel 1900 miles by car (one way) for a one week vacation
They wouldn’t. I don’t see how that’s relevant. If someone needs to travel from CA to NYC for a trip, a car isn’t even an option for them. If someone wants to go from Alaska to Texas, a car isn’t an option for them. Even if you banned most commercial flights, that doesn’t change the calculus. It just makes the remaining flights more expensive and forces people to find alternatives to get there. If a family decides they want to go to Disney World for a vacation, they’re going to pick the only method of travel that’s practical. They’re not going to go to Six Flags instead because they can get there by car.
You need to recheck your math. It doesn’t make sense to divide the consumption by plane but multiply by car.
https://yaleclimateconnections.org/2015/09/evolving-climate-math-of-flying-vs-driving/ https://sustainableamerica.org/blog/flying-or-driving-which-is-more-efficient/ http://websites.umich.edu/~umtriswt/PDF/UMTRI-2014-2_Abstract_English.pdf
“The main findings are that to make driving less energy intensive than flying, the fuel economy of the entire fleet of light-duty vehicles would have to improve from the current 21.5 mpg to at least 33.8 mpg, or vehicle load would have to increase from the current 1.38 persons to at least 2.3 persons.”
You can reject my argument but that just makes you wrong. Even the non-commute average load is still not enough to make the average long-distance trip more fuel efficient.
Also wrong.
“A new report from the University of Michigan’s Transportation Research Institute shows that flying has become 74% more efficient per passenger since 1970 while driving gained only 17% efficiency per passenger. In fact, the average plane trip has been more fuel efficient than the average car trip since as far back as 2000, according to their calculations.”
You’re talking out of your ass.
The math I used is an estimation, but a reasonable one. I didn’t divide by one and multiply by the other. I converted automobile MPG to MPG per passenger mile, by assuming various numbers of passengers.
If I burn a gallon of gas in a suburban, the suburban moves 27 miles. If I have 3 people on board, each moving 27 miles, the suburban has produces 81 passenger miles on a gallon of gas. That is 81 miles per gallon per passenger, or 81 passenger-miles per gallon.
If I put 3 more people on board, I produce 162 passenger miles on that same gallon of gas. The vehicle travels 27 miles, 6 passengers each travel 27 miles, passengers travel a total of 162 miles. One gallon of gas is burned. 162 passenger-miles per gallon, or mpg per person. The more people on board, the more efficiently the vehicle produces passenger-miles. (Obviously, the actual vehicle economy would fall slightly as I add weight, but the efficiency gains of carpooling would greatly exceed the negligible losses due to additional passenger weight)
I don’t know how many people were on the plane for the figures you provided. If I assume it was 200 people, then the plane’s economy is 67mpg/200, or 0.335mpg. If I assume 100 people, the plane’s economy is 0.67mpg. If I assume 67 people, the economy is 1mpg. All of these numbers are reasonable for jets capable of carrying a corresponding number of passengers.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
And I stand by my “no headway” claim, because I was careful to specify my meaning. There are viable options for transportation that do not rely on fossil fuels. Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today. The use of those vehicles is rising rapidly.
There are no commercially viable electric aircraft in the skies today, and no commercially viable alternatives to petroleum-based aviation fuel. Yes, the efficiency of those fossil fuels has increased, but no viable alternative is currently available, nor slated to be available in the near future.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point despite it being a rare occurrence. If you compared apples to apples and calculated both based on the average passenger count, you wouldn’t get the same amount. The only way your point stands is if you only factor in trips that are greater than 200km with 3+ passengers - something that would account for 5% of all automotive usage and wouldn’t make a measurable difference in the total amount of emissions from cars.
Except that no one was comparing airplanes to mass transit and, even if they were, this is not true unless you restrict it to a very, very narrow set of parameters. Buses can’t swim across oceans. Trains can’t either. There’s no practical alternative in many situations. My point, from the beginning, has been that there are other sectors who produce more emissions and are easier to fix than the emissions that airlines have. Unless we get those in-line first, there’s no point on focusing on aircraft and especially not in the context of going back to thinking like in the 1900s where people just don’t see their families.
And are nowhere near prevalent enough to offset the emissions of cars in use today to make them emit less than airplanes or make them more fuel efficient than airplanes. Unless every ride has 3+ passengers, what you’re saying is simply not true.
As are you.
There is no justification for your assumed average of 1.2 people per trip. You’re comparing “commutes” to things like “vacations”. I don’t take the wife and 4 kids with me to work; I do take them on vacation.
Even if we do assume a single rider, you don’t get to automatically assume “car”. An airplane is a mass-transit vehicle. A bus gives 180 to 300 MPG per passenger mile, and a train can be well over a thousand.
But we’re getting away from the point: whether by bus, car, train, plane, or even bicycle powered by a rider who consumes oxygen and expels CO2, the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip. We need to focus on reducing travel in general.
No, I’m not. Stop lying. I’m taking the average for both because that’s the only way to determine which is more fuel efficient and which sector has the most opportunity for a change.
No, I’m not. More lies. I used commutes initially because that was the most common usage for a car by a landslide which is the same thing I did for air travel. You weren’t ok with that so I used the more general number and took the total average for all types of rides in a car with any number of passengers at all distances. That number is 1.3 passengers per ride. Anything less than, taking a subsection of the rides to narrow it down to only rides with 3+ passengers and only for “vacations” or whatever other nonsense constraints you want to put on it, only reduces the total available impact since rides with 3+ passengers are already an extremely small percentage of rides in a car and “vacation travel” is an even smaller portion than that.
I didn’t. You guys used the example of a suburban. Emissions figures separate out mass transit from personal travel because they’re not comparable and mass transit has less opportunity for impact since it’s already the most sustainable method of transportation.
A complete straw man. If people need to get to a destination, going on a shorter trip is meaningless as is eliminating the trip. The most impactful changes are those that have the highest ROI in terms of barriers and resources. Airplanes ain’t that.
So it makes sense to divide planes mpg by passenger but not car mpg by passenger? Because the 67mpg you’re quoting is per passenger.
A 4 passenger car that gets 20mpg, what’s the mpg per passenger? Two ways to get to the result: fuel used is divided between passengers so each passenger uses 25% of the fuel, so 20mpg/25% = 80mpg per passenger OR even simpler, 20 mpg x 4 passengers. The result is the same. For planes, using my example from another comment, 82mpg/passenger, 388 passengers, 82/388 = 0.21mpg/passenger with one passenger.
Don’t tell me you truly believe that planes consume 67mpg by themselves because then you’ll have to explain why they need to cary thousands of gallons of fuel… (13k gallons for a 777)
Again, you’re comparing the average number of passengers for all road trips vs the average number of passengers for all airline trips, but the purpose of both isn’t the same and just because someone took a plane to go somewhere doesn’t mean they won’t be taking their car to work. Compare both travels for the same purpose (in this discussion, vacations) and people don’t tend to go on vacation alone, that increases the number of passengers in the car, they don’t tend to go as far in their car so that also lowers the amount of fuel used for the vacation.
For all purposes of travel, planes are more efficient. The longer a plane trip is the more efficient it is because the plane loses weight as you travel, not the other way around.
How can you ignore the multiple sources I’ve provided to still get the math wrong? Flying is more fuel efficient than cars. The only way you can make it less efficient is to limit the car rides to only rides that have 3+ passengers and only those that are multiple hundreds of miles in distance. That limits the trips we’re talking about to such a small percentage of auto travel that making progress in that specific area renders it meaningless. The majority of the carbon impact of driving comes from all the other usage. Airline travel has been more efficient than road travel since the start of the millennium.
For all purposes of travel, planes are more efficient. The longer a plane trip is *the more efficient it is* because the plane loses weight as you travel, not the other way around.The 67mpg/passenger number from the source I provided is based on trillions of miles traveled, don’t you think that’s taken into consideration?
I don’t get the math wrong, you interpret the data incorrectly and think that planes get 67mpg/vehicle instead of 67mpg/passenger and you compare car rides to work to long distance air travel instead of comparing leisure travel for both in which case cars are much more likely to be used for multi passenger travel.
No I don’t. I have never said that anywhere.
Stop lying and stop moving the goalposts.
Yes you do, you keep arguing as if it was the case!
No, I don’t. I’m arguing against your multiplication of the mpg of the Suburban because you arbitrarily picked 3 passengers. The 67mpg/passenger amount for planes is based on the average number of passengers in a plane. If we did what you’re doing and picked it based on ideal figures to suit our own points, the mpg for the plane would be even higher.
What was the average distance travelled by plane again? You keep dodging that part. If the plane is more efficient per passenger mile but people travel three to four times further when taking a plane for vacation vs a car then that means… oh my… plane vacations are less efficient because people use the fact that they travel quicker as a justification to go further away! 😱
Unless you think that the average American would travel 1900 miles by car (one way) for a one week vacation. Because if you think so then you’re truly hopeless.
What are you talking about?!
Planes are more efficient the farther the distance traveled! The average commercial flight was 900km for 2022. Planes still only account for 5% of the total emissions when including commercial, private, and transport flights and accounting for emissions from contrails. Now do that math for cars, trucks, and ground transport. Go ahead.
They absolutely do not. People choose their destination first and then they determine the mode of transport. No one changes their destination to someplace farther away because it takes less time to get there by plane than it does by driving.
They wouldn’t. I don’t see how that’s relevant. If someone needs to travel from CA to NYC for a trip, a car isn’t even an option for them. If someone wants to go from Alaska to Texas, a car isn’t an option for them. Even if you banned most commercial flights, that doesn’t change the calculus. It just makes the remaining flights more expensive and forces people to find alternatives to get there. If a family decides they want to go to Disney World for a vacation, they’re going to pick the only method of travel that’s practical. They’re not going to go to Six Flags instead because they can get there by car.