3 ms·

The "summary" in the example reports smells like someone has an agenda: > Compared to the legal limit of 30 mph, a typical vehicle driving at 36.1 mph takes an

The "summary" in the example reports smells like someone has an agenda: > Compared to the legal limit of 30 mph, a typical vehicle driving at 36.1 mph takes an extra 8.0 metres to stop, is 2.2 times more likely to kill a pedestrian on impact, generates 14.6% more CO2, 55.4% more NOx and produces 1.7 BA more noise. [emphasis mine] The stopping distance and likelihood to kill (though the not sure whether said likelihood is properly calculated as it's not a linear scale) is the only thing that should be relevant from a safety point of view which is the purported reason behind speed limits & their enforcement. The extra information seems like an attempt to sway the decision against the driver and further some environmentalist agenda.

gugagore 5y ago
Why aren't pollutants (chemical and noise) safety considerations for humans?
raldi 5y ago
> safety […] is the purported reason behind speed limits & their enforcement. A reason, among several others. See, for instance, the most famous speed limit ever enacted: https://en.wikipedia.org/wiki/National_Maximum_Speed_Law https://en.wikipedia.org/wiki/National_Maximum_Speed_Law
mistrial9 5y ago
> further some environmentalist agenda. poker response - I will see your "agenda" and raise you a "track cars all the time for ticket revenue agenda"
oceanplexian 5y ago
It's not an environmentalist agenda as much as a technique that media uses to mislead people. The more random statistics writers include, even if they are totally irrelevant, based on nonsense, or logically inconsistent, the more "informed" the readers feel when they skim the article. Once you include statistics it's no longer an opinion piece, but cold, hard fact backed by science... or something.
hansvm 5y ago
Collectively it's not totally unreasonable to limit things for environmental reasons (afaik the reduced fuel consumption in light of the Ukraine invasion might finally provide the impetus for limiting the Autobahn a little) -- laws exist to balance the desires of people, and the desire to drive faster might be found legally to be less important in its totality than whatever miniscule impact a 20% reduction in CO2 might have. The stats seem off though, almost exactly as if they normalized by time rather than distance. Most cars increase their fuel economy till 40-50, and the only way you'd see that significant of a jump in CO2 emissions per mile from 30 -> 36 is if it were coupled with an insane amount of stopping and also waiting to stop as long as possible so that the excess energy would have to be consumed by your brakes rather than air resistance (if you have regenerative braking obviously that point is a bit moot).
- sbradford26 5y ago
  Most likely it is theoretical fuel efficiency and not real world. A car will get it best fuel economy when traveling at the lowest speed where the engine can reach its peak efficiency band. You are fighting the least amount of air resistance and consuming the least amount of energy. Now in the real world this doesn't work out as well since where you drive at lows speeds tend to have a lot of stops. Where usually as once you hit 45-50 mph the roads will most likely have fewer stops.
  - hansvm 5y ago
    Ah, so maybe their models are just too simple? The 40-50 band being more efficient isn't just a function of stopping frequency -- you can directly measure it on your favorite long, stop-free stretch of road. Your engine has a nonlinear efficiency with respect to throttle position and load, and at low speeds those dominate fuel economy rather than increased air resistance. An engine optimized for efficiency would of course drive as slowly as possible, but other factors also contribute to the design of modern car engines.
tomatotomato37 5y ago
I always enjoy these statistics that assume a 50 year old SUV on bald tires has the exact same driving characteristics as a modern roadster on fresh summers. Turns out really the only difference between cars is aesthetics...

gugagore 5y ago

Why aren't pollutants (chemical and noise) safety considerations for humans?

raldi 5y ago

> safety […] is the purported reason behind speed limits & their enforcement. A reason, among several others. See, for instance, the most famous speed limit ever enacted: https://en.wikipedia.org/wiki/National_Maximum_Speed_Law https://en.wikipedia.org/wiki/National_Maximum_Speed_Law

mistrial9 5y ago

> further some environmentalist agenda. poker response - I will see your "agenda" and raise you a "track cars all the time for ticket revenue agenda"

oceanplexian 5y ago

It's not an environmentalist agenda as much as a technique that media uses to mislead people. The more random statistics writers include, even if they are totally irrelevant, based on nonsense, or logically inconsistent, the more "informed" the readers feel when they skim the article. Once you include statistics it's no longer an opinion piece, but cold, hard fact backed by science... or something.

hansvm 5y ago

Collectively it's not totally unreasonable to limit things for environmental reasons (afaik the reduced fuel consumption in light of the Ukraine invasion might finally provide the impetus for limiting the Autobahn a little) -- laws exist to balance the desires of people, and the desire to drive faster might be found legally to be less important in its totality than whatever miniscule impact a 20% reduction in CO2 might have. The stats seem off though, almost exactly as if they normalized by time rather than distance. Most cars increase their fuel economy till 40-50, and the only way you'd see that significant of a jump in CO2 emissions per mile from 30 -> 36 is if it were coupled with an insane amount of stopping and also waiting to stop as long as possible so that the excess energy would have to be consumed by your brakes rather than air resistance (if you have regenerative braking obviously that point is a bit moot).

sbradford26 5y ago
Most likely it is theoretical fuel efficiency and not real world. A car will get it best fuel economy when traveling at the lowest speed where the engine can reach its peak efficiency band. You are fighting the least amount of air resistance and consuming the least amount of energy. Now in the real world this doesn't work out as well since where you drive at lows speeds tend to have a lot of stops. Where usually as once you hit 45-50 mph the roads will most likely have fewer stops.
- hansvm 5y ago
  Ah, so maybe their models are just too simple? The 40-50 band being more efficient isn't just a function of stopping frequency -- you can directly measure it on your favorite long, stop-free stretch of road. Your engine has a nonlinear efficiency with respect to throttle position and load, and at low speeds those dominate fuel economy rather than increased air resistance. An engine optimized for efficiency would of course drive as slowly as possible, but other factors also contribute to the design of modern car engines.

tomatotomato37 5y ago

I always enjoy these statistics that assume a 50 year old SUV on bald tires has the exact same driving characteristics as a modern roadster on fresh summers. Turns out really the only difference between cars is aesthetics...