zlacker

>>CGMthr+(OP)
I cannot stop thinking about the fact that air travel wastes so much energy, just to float. Buoyancy is free.

It is insane that we are not doing materials research on how to capture vacuum in thin cavities.

>>whatev+QK2
Modern jetliners get a higher miles per gallon per seat than most US (ICE) cars. They easily beat any ICE car with a single occupant in miles per gallon equivalent. If you want to minimise fuel usage and can't find someone to share with, it's better to fly! The issue is almost entirely the distance travelled.

>>SPICLK+jP2
now do high speed rail..

>>riirif+D93
It varies so much depending on passenger occupancy rates. Planes tend to run near 100%, and cars (at least in the US, although I'm sure other countries aren't much better) at near 20%.

Assuming 1mpg for the entire train, it needs at least 100 passengers to compare to a fully-occupied passenger plane.

>>SPICLK+Oa3
Can you name a HSR route that exists between US cities that would challenge the near 100% occupancy rates? Seems relevant. We probably need to compare routes where there exists air travel and HSR to draw any occupancy rate choices, but this is clearly an aside.

The point is that it makes air travel ludicrous from an energy perspective where rail at high speeds (200mph) is possible

>>ririfd+rc3
Air travel is SO inefficient that it ONLY makes sense to fly with a full plane.

Train travel is so efficient that running nearly empty trains is just accepted.

>>bombca+eg3
You're joking, right?

Passenger capacity is part of the design of air travel. Even so, a plane could be at 1/3rd capacity before it's less efficient than a singly-occupied car.

Trains are largely a relic of the Industrial Revolution - except for those places where population distribution has made it feasible to invest in specialised passenger rail, the degree of infrastructure investment required makes them economically infeasible given a blank slate today.

If we were really concerned about transport efficiency, long-distance bus routes are the answer. Per-seat energy usage is comparable to trains, but with a fraction of the infrastructure cost, and significantly more flexibility. Countries that have a blank slate and are only interested in maximum transport for minimum cost (ie, the developing world) have gone that way for a reason.

We accept nearly empty trains, despite them needing at least 30 passengers to be competitive from a fuel efficiency standpoint with a singly-occupied car, because trains are largely seen as a service. Very few passenger trains are economically viable without government support.