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Comment by failwhaleshark | Hacker News Reader

Flying, in-general, is inefficient unless it's a large, lifting body in ground effect.

Flying on a full or almost-full plane is more carbon efficient than driving solo.

And that's not taking into account the cost of the road networks we build and maintain to allow high volumes of vehicular traffic.

https://yaleclimateconnections.org/2015/09/evolving-climate-...

> Flying on a full or almost-full plane is more carbon efficient than driving solo.

But how do they fare against trains, especially since trains can run on electricity? The mpg quoted in your article (21.6) also seems really low.

Oddly light rail in silicon valley uses more BTUs per passenger-mile than cars do. Of course that is caused by the fact that light rail has so few passengers (and the number has been falling even pre-covid).

>that's not taking into account the cost of the road networks we build and maintain

Well, why would you? Then you'd have to take into account the airports and the transportation networks to get to them...

Please do so. Airports are nothing compares to just I80 across the US. There are a lot of other roads as well that we could downgrade if more people flew.

I think autonomous vehicles will help here eventually too. A lot of road maintenance is due to large semi-trucks. If those vehicles are operated autonomously, they can be programmed to drive more efficiently in regards to wear on the roads. Slower braking, slower speeds (since you don’t need stops for drivers to sleep to reach your destination in the same amount of time).

We’d also see a closure of many roadside stops since there are no longer people around to use those facilities.

Road wear is caused by weight. Driving and braking slower won't make a significant difference.

Road damage is said to be proportional to the fourth power of axle weight [0]. The link to reference 14 on the article is dead but the internet archive has a copy of it at [1].

[0] https://en.wikipedia.org/wiki/Vehicle_weight#Importance

[1] https://web.archive.org/web/20150709151027/http://www.nvfnor...

An autonomous vehicle can keep the tires to the same track within 3cm. So there is potential to build pavement just where wheels go and corners.

I don't believe it, but it is possible.

Might also enable more frequent but smaller trucks, which also would enable more point to point movement of goods and less of a hub and spoke model.

The interstates tend to go to the airports though.

Interstates go a lots of places, airports is just one. they also cross Nebraska for example.

I would need more information to flesh out how you think my default assumptions (that indirect costs are approximately proportional to direct costs) should be revised.

Facts and logic are optional, but at least a quantitative assertion that's falsifiable would be a start.

> Flying on a full or almost-full plane is more carbon efficient than driving solo.

… in a fossil-fuel burning automobile. Do things changes with the rise of EVs?

Depends on where the electricity is coming from, and debatable if you account for all the externalities in producing the batteries, solar cells for photovoltaics, rare earth mining for magnets, and countless other stuff for way more silicon needed to regulate all that stuff to work efficiently together. Be it for in vehicle control, or smart grid.

On a 737 jammed to the gills. Now do the numbers on an sst with 50 people.

Maybe one time we manage to use something similar while flying supersonic with https://en.wikipedia.org/wiki/Compression_lift

I’d be interested to see a breakdown in fuel/seat-mile. I bet air travel isn’t as inefficient as the millions of people traveling alone in a car every day to work.

The thing is most people don’t drive their car 4000 miles across the Atlantic for a meeting.

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