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'Leave on time' OK. I have a 1.5 hour drive. I leave on time. I run across a driver doing 10mph under the speed limit. I'm late. OK, I leave 10m early. I run

'Leave on time' OK. I have a 1.5 hour drive. I leave on time. I run across a driver doing 10mph under the speed limit. I'm late. OK, I leave 10m early. I run across an accident. I'm late. OK, I leave 15m early. I run across a surprise document check and the officer is extra chatty. Combined with the traffic choke point I'm late. OK I leave 30m early for everywhere I go. I'm still late or early and never on time because I can't moderate my speed because someone thinks its 'risky'. Finally, the pollutes more argument doesn't hold up. Just because you have an 'eco' car doesn't mean its economical at traffic speeds. The safest way to drive is maintain the flow of traffic and be predictable (i.e. not slow and no unsafe hyper-mileing maneuvers), and suddenly cars that aren't underpowered microboxes are using less gas anytime you aren't doing 30mph in a city at constant speeds.

tgv 2y ago
What a coincidence that accidents happen when you leave early. > the pollutes more argument doesn't hold up The amount of energy required to travel the same distance increases with speed. This effect, I believe: https://en.wikipedia.org/wiki/Drag_(physics)#Power https://en.wikipedia.org/wiki/Drag_(physics)#Power. > The safest way to drive is maintain the flow of traffic and be predictable True, in which case a radar detector is no use, but rather dangerous.
- bradleyy 2y ago
  > The amount of energy required to travel the same distance increases with speed. Power from engines is not linear. Volumetric efficiency (engines are air pumps!) is not linear. The efficiency of a transmission is not linear. The amount of energy required to travel the same distance is not linear to speed, at all. Go 1 MPH somewhere, you'll have terrible gas mileage. This is precisely the exact opposite of what you're describing.
  - tgv 2y ago
    > The amount of energy required to travel the same distance is not linear to speed, at all. If it were linear, speed would have no effect on efficiency. > Power from engines ... But their efficiency can't improve with v^-3, so air friction wins. Just check the consumer reports on cars' fuel efficiency. Optimum efficiency is around 80km/h for most cars.
hunter2_ 2y ago
> not slow and no unsafe hyper-mileing maneuvers Which hyper-mileing maneuvers are unsafe other than going too slow? I assume there are some or else you wouldn't need to mention it following "not slow." Personally, I sometimes try to use just the right amount of fuel on an uphill such that once I crest the hill, I can maximize the duration/distance that I'm in complete overrun (fuel cut) before my speed drifts too far from the speed limit, and then I correct my speed at that point. Coasting to even lower speeds would improve MPG, but unsafe when followed, so I definitely avoid that. Cresting the hill well below the speed limit, knowing that the downhill will swiftly correct for that, isn't too risky in most situations.
- hmmm-i-wonder 2y ago
  Variable/intermittent speed for one. You deviate from the flow of traffic, making you unpredictable and thus unsafe.

tgv 2y ago

What a coincidence that accidents happen when you leave early. > the pollutes more argument doesn't hold up The amount of energy required to travel the same distance increases with speed. This effect, I believe: https://en.wikipedia.org/wiki/Drag_(physics)#Power https://en.wikipedia.org/wiki/Drag_(physics)#Power. > The safest way to drive is maintain the flow of traffic and be predictable True, in which case a radar detector is no use, but rather dangerous.

bradleyy 2y ago
> The amount of energy required to travel the same distance increases with speed. Power from engines is not linear. Volumetric efficiency (engines are air pumps!) is not linear. The efficiency of a transmission is not linear. The amount of energy required to travel the same distance is not linear to speed, at all. Go 1 MPH somewhere, you'll have terrible gas mileage. This is precisely the exact opposite of what you're describing.
- tgv 2y ago
  > The amount of energy required to travel the same distance is not linear to speed, at all. If it were linear, speed would have no effect on efficiency. > Power from engines ... But their efficiency can't improve with v^-3, so air friction wins. Just check the consumer reports on cars' fuel efficiency. Optimum efficiency is around 80km/h for most cars.

hunter2_ 2y ago

> not slow and no unsafe hyper-mileing maneuvers Which hyper-mileing maneuvers are unsafe other than going too slow? I assume there are some or else you wouldn't need to mention it following "not slow." Personally, I sometimes try to use just the right amount of fuel on an uphill such that once I crest the hill, I can maximize the duration/distance that I'm in complete overrun (fuel cut) before my speed drifts too far from the speed limit, and then I correct my speed at that point. Coasting to even lower speeds would improve MPG, but unsafe when followed, so I definitely avoid that. Cresting the hill well below the speed limit, knowing that the downhill will swiftly correct for that, isn't too risky in most situations.

hmmm-i-wonder 2y ago
Variable/intermittent speed for one. You deviate from the flow of traffic, making you unpredictable and thus unsafe.