5 ms·

When you have a fully automated motorway, with vehicles able to drive safely at any speed, I wonder what the cost and physical limitations of driving very very

When you have a fully automated motorway, with vehicles able to drive safely at any speed, I wonder what the cost and physical limitations of driving very very fast while still on the ground are, vs potentially flying.

Retric 11y ago
You get a lot more drag close to the ground. So, it depends on how 'fast' you mean by fast. Still, I think in and near city PRT will have a much larger impact. If you could average 40mph in and near city's that's a huge difference in peoples lives.
toomuchtodo 11y ago
Anything over ~80-90mph is going to be extremely inefficient due to drag coefficient.
- cmsmith 11y ago
  With sufficiently networked cars, you can reduce the following distance between cars and significantly reduce the drag coefficient. (Obviously there are safety issues, but we're playing the 'cars are smart enough to make everything perfectly safe' game)
- baldfat 11y ago
  Flew to Orlando from PA. Drive time would be 15 hours. Flight time is 2.25 hours. Left for airport at 7:30 am arrived home 8:45 pm (Traffic and just getting there 1.5 hours early and a non-direct flight) I saved 3.5 hours, but cost me hundreds of dollars. I think self-driving cars will change the way we travel to things on land that are 16 hours of driving or less.
  - Retric 11y ago
    It costs ~300$ to drive 1,000 miles. So, I don't think a few hundred is for a ticket is actually more expensive.
    - bjelkeman-again 11y ago
      Where I live I can travel in a electric car for roughly 1/6 of the cost of petrol. Of course the calculation is more complicated than that, cost of the vehicle, service etc. My guess is that this will be competitive with this type of air travel.
    - Shog9 11y ago
      Not for gas, not in the US right now, unless maybe you plan to travel in an old truck or some horribly inefficient sportscar. If you're factoring in wear and tear on your car, maybe... But highway driving isn't particularly hard on most vehicles either. The time invested is probably the most expensive part of driving, and that's where flying has been losing its lead for years.
      - Retric 11y ago
        There is a wide range of costs, but 30c/mile of highway driving is actually fairly cheap if you include everything. PS: "57.5 cents per mile for business miles driven, up from 56 cents in 2014" "The standard mileage rate for business is based on an annual study of the fixed and variable costs of operating an automobile, including depreciation, insurance, repairs, tires, maintenance, gas and oil."
    - mrfusion 11y ago
      What about a couple or a family though?
  - apercu 11y ago
    See, that's the thing. These days you need to hurry up to get the to airport hours before your flight, then wait. Etc... I do this a lot flying to Ottawa. Leave at 6am, get home at 10:00pm. I'd consider driving if the car was autonomous.
  - leephillips 11y ago
    But during most of that time you could read, work on a laptop, etc. Not so when driving.
    - mrfusion 11y ago
      Just the two hours of flight time actually. Otherwise you're driving, waiting in line, walking, getting luggage, etc
  - apendleton 11y ago
    Yeah, I think this gets especially fascinating if people don't own their own vehicles. Uber, etc., are pretty big now, but they're still employing people with regular off-the-shelf cars. I think eventually we could reach a tipping point where most people don't own their own vehicles and Uber, etc., get so large that it makes sense for them to start building/buying purpose-built vehicles that could be dispatched according to your particular task. Commuting solo? You get a super-fuel-efficient one-seater. Driving 16 hours? You get a car with a bed in it, and your trip will take place overnight. Go to sleep in PA, wake up in Orlando. And so forth.
  - peteretep 11y ago
    That's an interesting point, and also seems to fit in to the supersonic jet narrative: people aren't willing to pay a (sufficient) premium to shave a few hours off a flight. In the same way, you might be willing to accept a couple of extra hours travel time to be in the comfort of your own vehicle.
- Chris2048 11y ago
  underground evacuated chamber?
  - toomuchtodo 11y ago
    Electric cars locally, hyperloop for greater distances, aircraft running on biofuels as a last resort.
- alkonaut 11y ago
  Assuming we have fully electric cars and "solved" the electricity production problem, I don't see the inefficiency of going fast at ground level as being a significant problem. That's a big "if" though.
  - ksrm 11y ago
    The problem is that at motorway driving speeds, where air resistance is dominant, the power required is proportional to the cube of the velocity. Driving at 100 mph instead of 80 mph will halve your range.
    - alkonaut 11y ago
      Cube? I was almost sure it was square
Shivetya 11y ago
you could reduce some aerodynamic drive by putting the cars end to end. essentially your car knows its destination and moves to the appropriate lane, the further you need to travel the more likely you end up in a far lane where cars are kept at a higher pace and closer together. think of it as a modern version of Chicago highways where the left lanes get sectioned off on occasion with less chances to exit all to keep people in lanes consistently to reduce accidents from moving lane to lane. fully autonomous cars and lanes dedicated to them and similar buses will remove the need for rail with in city limits beyond what exist. with no need to transfer vehicles and dedicated lanes you don't need as much planning for changes in travel patterns. fixed rail is always trapped, worse you end up with periods where you have too much capacity or too little and the inflexibility of track means no one else can use it. dedicate roadways can use the same space and be entirely flexible with easier maintenance and lower overall costs
- sloppycee 11y ago
  In Toronto we have the collector/express system for the 401, it is still a mess: https://upload.wikimedia.org/wikipedia/commons/f/f9/Highway_401.png https://upload.wikimedia.org/wikipedia/commons/f/f9/Highway_... At a certain scale congestion is inevitable, whether automated or not, faster traffic will eventually need to merge with slower traffic...
speedthrowafff 11y ago
At 200+ mph it becomes hard to stay on the ground. :)
lumberjack 11y ago
Why would you have an automated motorway? Why not have rail instead and get a self driving cab from the terminal to your final destination. Self driving cars make more sense for short distances.
- clock_tower 11y ago
  Railroads are better than self-driving cars for most purposes -- more efficient, safer, simpler to maintain, and _much_ less complicated to create -- but the US apparently doesn't have the political will to build new ones anymore. It reminds me of the failed attempt to upgrade the air-traffic control system back in the '80s and '90s...

Retric 11y ago

You get a lot more drag close to the ground. So, it depends on how 'fast' you mean by fast. Still, I think in and near city PRT will have a much larger impact. If you could average 40mph in and near city's that's a huge difference in peoples lives.

toomuchtodo 11y ago

Anything over ~80-90mph is going to be extremely inefficient due to drag coefficient.

cmsmith 11y ago
With sufficiently networked cars, you can reduce the following distance between cars and significantly reduce the drag coefficient. (Obviously there are safety issues, but we're playing the 'cars are smart enough to make everything perfectly safe' game)
baldfat 11y ago
Flew to Orlando from PA. Drive time would be 15 hours. Flight time is 2.25 hours. Left for airport at 7:30 am arrived home 8:45 pm (Traffic and just getting there 1.5 hours early and a non-direct flight) I saved 3.5 hours, but cost me hundreds of dollars. I think self-driving cars will change the way we travel to things on land that are 16 hours of driving or less.
- Retric 11y ago
  It costs ~300$ to drive 1,000 miles. So, I don't think a few hundred is for a ticket is actually more expensive.
  - bjelkeman-again 11y ago
    Where I live I can travel in a electric car for roughly 1/6 of the cost of petrol. Of course the calculation is more complicated than that, cost of the vehicle, service etc. My guess is that this will be competitive with this type of air travel.
  - Shog9 11y ago
    Not for gas, not in the US right now, unless maybe you plan to travel in an old truck or some horribly inefficient sportscar. If you're factoring in wear and tear on your car, maybe... But highway driving isn't particularly hard on most vehicles either. The time invested is probably the most expensive part of driving, and that's where flying has been losing its lead for years.
    - Retric 11y ago
      There is a wide range of costs, but 30c/mile of highway driving is actually fairly cheap if you include everything. PS: "57.5 cents per mile for business miles driven, up from 56 cents in 2014" "The standard mileage rate for business is based on an annual study of the fixed and variable costs of operating an automobile, including depreciation, insurance, repairs, tires, maintenance, gas and oil."
  - mrfusion 11y ago
    What about a couple or a family though?
- apercu 11y ago
  See, that's the thing. These days you need to hurry up to get the to airport hours before your flight, then wait. Etc... I do this a lot flying to Ottawa. Leave at 6am, get home at 10:00pm. I'd consider driving if the car was autonomous.
- leephillips 11y ago
  But during most of that time you could read, work on a laptop, etc. Not so when driving.
  - mrfusion 11y ago
    Just the two hours of flight time actually. Otherwise you're driving, waiting in line, walking, getting luggage, etc
- apendleton 11y ago
  Yeah, I think this gets especially fascinating if people don't own their own vehicles. Uber, etc., are pretty big now, but they're still employing people with regular off-the-shelf cars. I think eventually we could reach a tipping point where most people don't own their own vehicles and Uber, etc., get so large that it makes sense for them to start building/buying purpose-built vehicles that could be dispatched according to your particular task. Commuting solo? You get a super-fuel-efficient one-seater. Driving 16 hours? You get a car with a bed in it, and your trip will take place overnight. Go to sleep in PA, wake up in Orlando. And so forth.
- peteretep 11y ago
  That's an interesting point, and also seems to fit in to the supersonic jet narrative: people aren't willing to pay a (sufficient) premium to shave a few hours off a flight. In the same way, you might be willing to accept a couple of extra hours travel time to be in the comfort of your own vehicle.
Chris2048 11y ago
underground evacuated chamber?
- toomuchtodo 11y ago
  Electric cars locally, hyperloop for greater distances, aircraft running on biofuels as a last resort.
alkonaut 11y ago
Assuming we have fully electric cars and "solved" the electricity production problem, I don't see the inefficiency of going fast at ground level as being a significant problem. That's a big "if" though.
- ksrm 11y ago
  The problem is that at motorway driving speeds, where air resistance is dominant, the power required is proportional to the cube of the velocity. Driving at 100 mph instead of 80 mph will halve your range.
  - alkonaut 11y ago
    Cube? I was almost sure it was square

Shivetya 11y ago

you could reduce some aerodynamic drive by putting the cars end to end. essentially your car knows its destination and moves to the appropriate lane, the further you need to travel the more likely you end up in a far lane where cars are kept at a higher pace and closer together. think of it as a modern version of Chicago highways where the left lanes get sectioned off on occasion with less chances to exit all to keep people in lanes consistently to reduce accidents from moving lane to lane. fully autonomous cars and lanes dedicated to them and similar buses will remove the need for rail with in city limits beyond what exist. with no need to transfer vehicles and dedicated lanes you don't need as much planning for changes in travel patterns. fixed rail is always trapped, worse you end up with periods where you have too much capacity or too little and the inflexibility of track means no one else can use it. dedicate roadways can use the same space and be entirely flexible with easier maintenance and lower overall costs

sloppycee 11y ago
In Toronto we have the collector/express system for the 401, it is still a mess: https://upload.wikimedia.org/wikipedia/commons/f/f9/Highway_401.png https://upload.wikimedia.org/wikipedia/commons/f/f9/Highway_... At a certain scale congestion is inevitable, whether automated or not, faster traffic will eventually need to merge with slower traffic...

speedthrowafff 11y ago

At 200+ mph it becomes hard to stay on the ground. :)

lumberjack 11y ago

Why would you have an automated motorway? Why not have rail instead and get a self driving cab from the terminal to your final destination. Self driving cars make more sense for short distances.

clock_tower 11y ago
Railroads are better than self-driving cars for most purposes -- more efficient, safer, simpler to maintain, and _much_ less complicated to create -- but the US apparently doesn't have the political will to build new ones anymore. It reminds me of the failed attempt to upgrade the air-traffic control system back in the '80s and '90s...