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There is a missing piece of information here. Lower vehicle speeds are actually worsen pollution per mile. The optimum fuel economy for most ice vehicles is aro

There is a missing piece of information here. Lower vehicle speeds are actually worsen pollution per mile. The optimum fuel economy for most ice vehicles is around 40 miles/hour. Anything below or above that will increase the pollution per mile. So what cities should do is: lower speeds for all personal transport. Speed up busses to 40miles/hour. Give the busses special lanes everywhere. Increase the amount of public transport. Increase it so much that you can just travel without an itinerary. Make public transport faster that private transport.

toomuchtodo 3y ago
This is immaterial considering EV ramp rate and overall fleet turnover trajectory. Public transportation is also non existent in most of the US. Agree with your mass transit points where density and planning allows (bus lanes, fast busses, even free bus rides). Importantly, an EV rideshare fleet should be considered where using bus routes is inefficient to due low density. Congestion charges are also likely helpful where there is high density (Manhattan, Chicago Loop, parts of they Bay Area, Washington state, Philadelphia, Washington DC, etc). TLDR: Mass transit, lower speed limits, and traffic calming in urban (and suburban, where reasonable) areas. Electrification for middle of nowhere. https://www.utilitydive.com/news/electric-vehicles-EVs-new-car-sales-2023/700799/ https://www.utilitydive.com/news/electric-vehicles-EVs-new-c... https://www.atlasevhub.com/weekly-digest/one-million-evs-sold-through-september-2023/ https://www.atlasevhub.com/weekly-digest/one-million-evs-sol... https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehicles https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehic... https://vividmaps.com/public-transportation-in-the-united-states/ https://vividmaps.com/public-transportation-in-the-united-st... https://www.census.gov/newsroom/press-releases/2021/public-transportation-commuters.html https://www.census.gov/newsroom/press-releases/2021/public-t...
euroderf 3y ago
How about an automatic transmission that can upshift to top gear even at modest speeds, and the tradeoff is that very little additional torque-on-demand is available ?
- coryrc 3y ago
  They do, they just unlock the torque converter or downshift as you accelerate. They shift to top gear before the equivalent manual does, and you'll find automatics have significantly lower gear ratios than the manual transmission of the same vehicle. This is the only reason their gas mileage is close to manual transmissions, because manual is ~97% efficient while automatics are 85-90% -- planetary has 3x the mating surfaces plus there are three (or more) sets of them. Typically third gear is straight through and what you get when you disengage OD, which is half the reason you use it when towing.
  - jerlam 3y ago
    While manuals may be more efficient, most cars with automatic transmissions now have the same or even slightly better estimated gas mileage than cars with manual transmissions, assuming you can even find the latter.
    - coryrc 3y ago
      Yes, because the lower gear ratio of the automatic allows the gasoline engine to operate in a more efficient portion of the bsfc curve, which makes up for the substantially higher transmission losses.

toomuchtodo 3y ago

This is immaterial considering EV ramp rate and overall fleet turnover trajectory. Public transportation is also non existent in most of the US. Agree with your mass transit points where density and planning allows (bus lanes, fast busses, even free bus rides). Importantly, an EV rideshare fleet should be considered where using bus routes is inefficient to due low density. Congestion charges are also likely helpful where there is high density (Manhattan, Chicago Loop, parts of they Bay Area, Washington state, Philadelphia, Washington DC, etc). TLDR: Mass transit, lower speed limits, and traffic calming in urban (and suburban, where reasonable) areas. Electrification for middle of nowhere. https://www.utilitydive.com/news/electric-vehicles-EVs-new-car-sales-2023/700799/ https://www.utilitydive.com/news/electric-vehicles-EVs-new-c... https://www.atlasevhub.com/weekly-digest/one-million-evs-sold-through-september-2023/ https://www.atlasevhub.com/weekly-digest/one-million-evs-sol... https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehicles https://en.wikipedia.org/wiki/Phase-out_of_fossil_fuel_vehic... https://vividmaps.com/public-transportation-in-the-united-states/ https://vividmaps.com/public-transportation-in-the-united-st... https://www.census.gov/newsroom/press-releases/2021/public-transportation-commuters.html https://www.census.gov/newsroom/press-releases/2021/public-t...

euroderf 3y ago

How about an automatic transmission that can upshift to top gear even at modest speeds, and the tradeoff is that very little additional torque-on-demand is available ?

coryrc 3y ago
They do, they just unlock the torque converter or downshift as you accelerate. They shift to top gear before the equivalent manual does, and you'll find automatics have significantly lower gear ratios than the manual transmission of the same vehicle. This is the only reason their gas mileage is close to manual transmissions, because manual is ~97% efficient while automatics are 85-90% -- planetary has 3x the mating surfaces plus there are three (or more) sets of them. Typically third gear is straight through and what you get when you disengage OD, which is half the reason you use it when towing.
- jerlam 3y ago
  While manuals may be more efficient, most cars with automatic transmissions now have the same or even slightly better estimated gas mileage than cars with manual transmissions, assuming you can even find the latter.
  - coryrc 3y ago
    Yes, because the lower gear ratio of the automatic allows the gasoline engine to operate in a more efficient portion of the bsfc curve, which makes up for the substantially higher transmission losses.