5 ms·

This is great news, until we look at the open space and say, "Wow! Now we can fit so many more commuters on these streets." Nature abhors a vacuum. Not to den

This is great news, until we look at the open space and say, "Wow! Now we can fit so many more commuters on these streets." Nature abhors a vacuum. Not to denigrate the science, I respect the math greatly. It's just that NYC culture is about trying to cram the most things in one place. Few open resources like Central Park remain so very long.

gajomi 10y ago
>This is great news, until we look at the open space and say, "Wow! Now we can fit so many more commuters on these streets." >It's just that NYC culture is about trying to cram the most things in one place. One possibility in this case is to just fill the streets with people in the way they transiently get filled during coordinated street closures and in the way they are more or less permanently so in the right areas of Barcelona, Paris, Pattaya, etc. This would take a lot of planning and lobbying to get done right I imagine.
deleted 10y ago
[deleted]
usrusr 10y ago
But nature seems to just not abhor the "vacuum" left in cars filled with just a single rider hard enough to fill that. This is about finding a lower bound for the vehicles needed to fulfill demand with multi-occupancy. What I would find even more interesting is if they used the same simulation to determine the number of cars required to fulfill that demand without multi-occupancy, but with the same level of dispatch smarts and similarly strict optimization for the lowest number of cars possible. Why would this be interesting? There are not 13000 cabs because less would not be able to meet the existing demand, there are 13000 cabs because the market is big enough to support them (and decisions regarding the volume of the medallion system are surely not done with the optimization vigor as researchers looking for an impressive lower bound in a simulation). Hailable transportation is a very special market where more supply only increases instant hailability, but does not have the conventional effect of decreasing prices. And because more supply means more congestion, it can even increase prices (when rates have a time component on top of a distance component) and demand (when permanent congestion makes it unattractive to have a personal vehicle).
- madgar 10y ago
  > But nature seems to just not abhor the "vacuum" left in cars filled with just a single rider hard enough to fill that. I'm not sure exactly what this sentence is supposed to mean, but I assure you as an NYC outer-borough resident, if you created a traffic vacuum in manhattan I would be driving there filling the vacuum by the end of the day.
  - chillingeffect 10y ago
    I believe what they're saying refers to the empty 3 seats you might find in a singly-occupied 4 passenger car, as is often seen commuting. And I basically agree. There is still space in many passenger vehicles. And the vacuum is not strong to get those filled, because it is not infinite or even powerful enough, but there are people trying to fill those spaces to some extent. That was some of the original pitch of the "sharing economy..." That if you had "extra space in your car or house," you could fill it with a rider or a roomer. It's just that managing the complexities of the extra space in a vehicle is very difficult, particularly in comparison to the simplicity of filling any empty Manhattan streets with new instances of vehicles.
akgerber 10y ago
"Induced demand" is the bane of attempt to reduce congestion in the history of automobiles. https://en.wikipedia.org/wiki/Induced_demand https://en.wikipedia.org/wiki/Induced_demand
ufo 10y ago
Its not just about NYC. The vacuum problem is a real issue for congestion. During peak hours there are plenty of people with cars that avoid the road due to traffic but would jump right in if the roads were less congested. So increased supply in road space (due to building new roads or this hypothetical carpooling scheme) is immediately met by additional driver demand and congestion quickly returns to where it was before.

gajomi 10y ago

>This is great news, until we look at the open space and say, "Wow! Now we can fit so many more commuters on these streets." >It's just that NYC culture is about trying to cram the most things in one place. One possibility in this case is to just fill the streets with people in the way they transiently get filled during coordinated street closures and in the way they are more or less permanently so in the right areas of Barcelona, Paris, Pattaya, etc. This would take a lot of planning and lobbying to get done right I imagine.

deleted 10y ago

[deleted]

usrusr 10y ago

But nature seems to just not abhor the "vacuum" left in cars filled with just a single rider hard enough to fill that. This is about finding a lower bound for the vehicles needed to fulfill demand with multi-occupancy. What I would find even more interesting is if they used the same simulation to determine the number of cars required to fulfill that demand without multi-occupancy, but with the same level of dispatch smarts and similarly strict optimization for the lowest number of cars possible. Why would this be interesting? There are not 13000 cabs because less would not be able to meet the existing demand, there are 13000 cabs because the market is big enough to support them (and decisions regarding the volume of the medallion system are surely not done with the optimization vigor as researchers looking for an impressive lower bound in a simulation). Hailable transportation is a very special market where more supply only increases instant hailability, but does not have the conventional effect of decreasing prices. And because more supply means more congestion, it can even increase prices (when rates have a time component on top of a distance component) and demand (when permanent congestion makes it unattractive to have a personal vehicle).

madgar 10y ago
> But nature seems to just not abhor the "vacuum" left in cars filled with just a single rider hard enough to fill that. I'm not sure exactly what this sentence is supposed to mean, but I assure you as an NYC outer-borough resident, if you created a traffic vacuum in manhattan I would be driving there filling the vacuum by the end of the day.
- chillingeffect 10y ago
  I believe what they're saying refers to the empty 3 seats you might find in a singly-occupied 4 passenger car, as is often seen commuting. And I basically agree. There is still space in many passenger vehicles. And the vacuum is not strong to get those filled, because it is not infinite or even powerful enough, but there are people trying to fill those spaces to some extent. That was some of the original pitch of the "sharing economy..." That if you had "extra space in your car or house," you could fill it with a rider or a roomer. It's just that managing the complexities of the extra space in a vehicle is very difficult, particularly in comparison to the simplicity of filling any empty Manhattan streets with new instances of vehicles.

akgerber 10y ago

"Induced demand" is the bane of attempt to reduce congestion in the history of automobiles. https://en.wikipedia.org/wiki/Induced_demand https://en.wikipedia.org/wiki/Induced_demand

ufo 10y ago

Its not just about NYC. The vacuum problem is a real issue for congestion. During peak hours there are plenty of people with cars that avoid the road due to traffic but would jump right in if the roads were less congested. So increased supply in road space (due to building new roads or this hypothetical carpooling scheme) is immediately met by additional driver demand and congestion quickly returns to where it was before.