4 ms·

Alternate idea (which could be enabled by tele-op trucks) - make trucks go slower. Make them stick in the right couple lanes and give them a lower speed limit.

• bluGill 4y ago
  Turns out many cars and trucks are more efficient at 65mph (120km/h) than 55mph (100km/h). There are a lot of fixed losses, and ideal engine RPM is critical for efficiency.
  • elil17 4y ago
    Going too slow is definitely inefficient for non-hybrid cars and trucks, but the optimal speed for most vehicles is certainly not higher than 55 MPH. Average fuel economy for cars and light trucks decreases 12% going from 50 to 60 MPH: https://www.energy.gov/eere/vehicles/fact-982-june-19-2017-slow-down-save-fuel-fuel-economy-decreases-about-14-when https://www.energy.gov/eere/vehicles/fact-982-june-19-2017-s... Heavy trucks are the exception, they are typically designed for an operating point of 65 MPH. However, there are huge losses above that speed. No reason for a heavy truck to be going 70 or 75 MPH. The American Trucking Association actually endorses a nation 65 MPH speed limit for trucks, which they say would save 280 million gallons of diesel per year: https://www.fleetowner.com/emissions-efficiency/article/21660208/fuel-economy-101 https://www.fleetowner.com/emissions-efficiency/article/2166...
  • rightbyte 4y ago
    Really? The graphs I have seen put the optimal ICE car speed at about 30-50 mph depending on car aerodynamics. For EVs it is probably even lower as drag dominate earlier.
  • bryanlarsen 4y ago
    The Tesla Model 3's computer's range calculator gives a max efficiency at 22mph.
    • londons_explore 4y ago
      In my gasoline car, max efficiency is at 29 mph, or 35 if it's dark, cold and raining (energy use of lights, fan and wipers is minimised by driving faster so you need the lights for fewer hours to go the same distance)
• ct0 4y ago
  Momentum is a massive benefit that trucks try to leverage. I fully support truck lanes though, as cars are generally the cause for losing momentum on on ramps etc.
  • jessaustin 4y ago
    Separating different types of traffic could be a good idea, but there's no free lunch in physics. Higher speeds require more energy, period. Heavier loads require more energy, period. Wasting momentum due to curvy roads or traffic is inefficient, but higher speeds don't somehow make up for that.
  • elil17 4y ago
    Maybe speed limits are the wrong idea - you probably do want trucks to be able to speed up above their cruising speed before going up a hill. But dedicated lanes and tele-op could set up an incentive structure that favors a lower speed without any laws.
• nradov 4y ago
  No thanks. Try driving on highway truck route like I-5 where there are only 2 lanes in each direction. Even when the trucks stick to the right lane that still results in long delays as everyone else tries to pass on the left. Slowing the trucks down even more will just cause further delays, road rage, and dangerous driving.
  • rad_gruchalski 4y ago
    Oh, don’t worry. We’ll add more sensors and real-time monitoring to passenger cars so we’ll becable to punish those doing road rage. We’ll also put a hard speed limit in place which will be enforced electronically by the car itself. We will then eliminate all old cars by raising taxes on them beyound what any sane person would pay. It’s coming. Total control.
  • elil17 4y ago
    Or just do it where it makes sense and don't do it on two lane roads. Doesn't have to be an all-or-nothing policy. Many roads already have lower speed limits and lane restrictions for trucks. That could easily be expanded where it makes sense.
  • lostapathy 4y ago
    > Even when the trucks stick to the right lane that still results in long delays as everyone else tries to pass on the left. I'm always amazed in the midwest what a difference there is between traffic in states that have (and actually enforce!) a "get out of the left lane" law vs states that don't. I-80 across the eastern half of Iowa in particular is exhausting to drive on, because a lot of people camp in the left lane and clog up traffic. That leads to desperate and aggressive driving to get around these silly bottlenecks, which kills fuel efficiency and makes the roads more dangerous.
    • midoridensha 4y ago
      >I'm always amazed in the midwest what a difference there is between traffic in states that have (and actually enforce!) a "get out of the left lane" law vs states that don't. Those laws are unAmerican: they're about people doing what's best for the common good, instead of being selfish, and that's completely contrary to American ethics and mindset. That's why Americans generally hate those "keep right except to pass" signs and ignore them.
• andbberger 4y ago
  or or, hear me out, become switzerland and get serious about doing freight logistics with trains