
Study: carpooling apps could reduce traffic 3x in NYC - belltaco
https://www.csail.mit.edu/ridesharing_reduces_traffic_300_percent
======
awjr
I find the focus on congestion within the transport space to be perplexing.
I'm guessing it is to do with the visibility of congestion. Waze recently did
a survey and identified the Netherlands as the best place to drive
([https://www.waze.com/driverindex](https://www.waze.com/driverindex)).

The Netherlands is also the only western country with a negative obesity trend
expected to hit 8% by 2030, currently at 10% vs the UK's 25%. The USA I
believe is getting close to 36%.

We can try and blame our diets, however our built environment is creating a
public health crisis of inoordinate scale. The car is very much to blame for
this.

The car and car sharing is not the answer to traffic. Creating segregated end
to end cycle networks with good junctions enabling people to choose to ride up
to 5 miles to school/work is absolutely critical to avert this public health
crisis.

~~~
source99
Much of the academic research I have read (Check out Good Calories, Bad
Calories by Gary Taubes) shows the exact opposite to be true.

Our diets accounts for dramatically much higher cause of obesity than our
environment and specifically cars.

~~~
ceras
Diet definitely has a bigger impact than exercise, but isn't there still a
correlation between more urban areas and lower obesity even when controlling
for poverty?

There may be other factors to urban, non-car-based living besides the extra
physical activity that encourages lower weight. It's maybe as simple as
without a car you can't go to Costco and stock up on huge sacks of unhealthy
foods in one go -- beats me, I'd be interested to learn more.

~~~
akiselev
On my phone so I can't find the right metastudy but yes, there is an inverse
correlation between urban lifestyles and obesity rates but it's a tenuous one.
In cities like Atlanta, St. Louis, Montgomery, and San Antonio the difference
in obesity rates from rural and suburban areas in the same state is almost
nonexistent but Houston, Los Angeles, San Francisco, and New York see much
lower rates in obesity. (within city limits, their metropolitan areas are a
while different animal).

I have a feeling that it's mostly due to a hybrid peer pressure/economic
effect. When you're in a group of friends and the majority want to go to a
healthier restaurant or everyone in your neighborhood goes to the local mom
and pop grocery store instead of Safeway, it becomes a self reinforcing
pressure to eat healthy. More healthy restaurants will open and more small
grocery stores will be built to serve individual neighborhoods while market
share is slowly taken from unhealthy restaurants and chain groceries.
Eventually, a significant portion of people who would otherwise have trouble
controlling their weight stick with the healthier diet out of inertia or
convenience.

I also saw a study (although not a very conclusive one) that suggested that
discrimination could play a part. A higher cost of living in cities means that
a lot more jobs that can support the lifestyle have a physical appearance
component to them. Salespeople in high end boutiques, consultants, etc are
economically more viable in denser areas and if clients or employers
discriminate based on looks, there will be fewer job opportunities for the
obese, making it harder for them to live in urban areas.

~~~
moyix
Do you know if there's a study that breaks this down by population density
instead? My intuition (having lived for 6 years without a car in Atlanta) is
that obesity levels aren't going to be significantly different in a sprawling,
low-density city like Atlanta, where everyone drives, but in a dense,
walkable, and public-transit friendly city like NYC you will see a difference.

~~~
akiselev
Not off the top of my head but there are plenty of such studies. That still
wouldn't give a clear picture because Los Angeles is also a low density car
centric city but because it's in California, healthy eating is culturally more
prevalent and fresh food is easier to come by.

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99_00
In India I experienced low tech ride sharing. You stand at an intersection and
a three wheeler asks you where you're going. You get in, and the driver heads
to a major intersection near your destination.

Along the way he asks other people standing at intersections if they are going
his way, and if they are they pile in. The more people he stuffs into his
three wheeler the more money he makes per trip.

It was an unpleasant ride.

~~~
danesparza
+1 for 'it was an unpleasant ride'. I think that's the biggest friction point
many ride sharing apps face.

~~~
nashashmi
Subways are also an unpleasant ride at the moment. But if it is cheap enough,
why not?

~~~
johansch
Subways are primarily unpleasant because of the (worst parts of the)
clientele, not because of the rider density. Just the simple act of requiring
riders to have a credit card will get rid of >90% of the unpleasant co-riders.

~~~
ryanx435
What is the point of public transportation if you don't want the public to use
it?

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CodeSheikh
New York City includes Brooklyn, Queens, Bronx and Staten Island as well.
Misleading title and perhaps incomplete study if footprint of cabs is not
included from those remaining boroughs in this study. If you live in
Manhattan, then you don't use cabs as much within Manhattan because subways
cover Manhattan pretty well and travel times in cabs are hellish comparing to
subway commute. You often use cabs when you commute to other boroughs from
Manhattan because, for example, Brooklyn and Queens do not have great subway
network.

~~~
guessmyname
I didn't know how big New York City was until I went from Central Park (North
side) to the Brooklyn Botanic Garden... walking... never again!

~~~
cleetus
For my 30th bday, some friends and I walked around the perimeter of Manhattan.
It took just over 20 hours, but that's mostly because we stopped several at
bars along the way.

~~~
pavel_lishin
There's a yearly event that does this, called The Great Saunter. A friend of
mine did it last year, and we met her and walked for a mile or so.

It took her and most others around 12 hours; I can easily believe 20 if you're
stopping at bars along the way :P

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JoeAltmaier
And a grid of regular bus service could replace every car in LA. That'd be a
harder sell though.

~~~
JBReefer
Yeah but I bet you can't name 15 cities larger than LA that depend on an
outdated tech like trains. When's the last time you saw one of those at
TechCrunch Disrupt?

Seriously though, this is a solved problem everywhere but major US cities.
Paris - which once loved cars - has totally changed over to being bus, bike,
and train promoting, and it works.

~~~
LordKano
There are cultural reasons why what works in Europe won't work in most of the
US.

If I can't take my car or park for a reasonable fee, I simply won't go
somewhere and most of the people I know are the same.

~~~
cashmonkey85
I see this in Tokyo. Americans just stuck at home, stranded and helpless
because of their culturally reasons. Oh no wait they just use the awesome
public transport system. But it's very difficult for them to enjoy such
efficience because...you..know...culture

~~~
chongli
Huh? Americans don't have a cultural aversion to using world class public
transit when in a place like Tokyo. They have a cultural aversion to altering
their cities in the radical ways that'd be necessary to build a functional
public transit. They call this NIMBY.

~~~
rhino369
It's not really even cultural. It is a socio-economic and technological issue.
Every rich country that settled new territory or experienced massive growth
after the invention of the car has cities that are spread out.

Europe was already developed pre-car. Asia had huge population growth when
their people generally couldn't afford cars.

This is why US cities that were big before the Model T have a dense core with
decent public transit. And cities that exploded after the Model T are
basically suburbs of themselves, LA, Houston, Jacksonville. It's always why
newly formed European suburbs often are just as car reliant as US suburbs.
Though it's worth noting that some European suburbs existed before cars and at
the time were just outlying cities that now got subsumed into the metro area.

If Japan had a new city naturally develop in an open area, it would a lot more
like LA than Tokyo.

~~~
Retric
DC in the US is a solid counter example as low density city older than the
car. Density is based on a huge range of factors with for example geography
playing a significant role. Another huge factor is they type of industry.
Garment factory's for example have historically had very high density's where
Iron Works are much lower density.

~~~
rhino369
DC is a pretty good counter example. As you say the type of work matters, and
DC has never an industrial town. It was also a planned city. It was intended
to not be dense from the start. Something like 40% of DC is federal government
land.

DC also is doing a decent job at using mass transit to re-densify areas. The
orange line corridor is making suburbs become dense. That is pretty unique in
America.

~~~
antisthenes
[https://en.wikipedia.org/wiki/List_of_United_States_cities_b...](https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population_density#Incorporated_places_with_a_density_of_over_10.2C000_people_per_square_mile)

For a city that was "intended to not be dense from the start", it sure is up
there as far as density and would be #16 on the list if it counted as a part
of a state.

DC is incredibly dense by American standards and is actually one of the very
few places in the US that you can get by without a car (which is, of course,
priced into exorbitant rents and property prices)

I guess what I meant to say is that the grandparent comment is blatantly
false. DC _is_ a high density city and is much more like a European city in
that it combines decent public transport and medium-rise developments.

~~~
Retric
[https://en.wikipedia.org/wiki/Paris](https://en.wikipedia.org/wiki/Paris)

    
    
      DC has 158.1 km2 with 681,170 people or 4,308 people per km ^2.
    
      Paris has 105.4 km2 with 2,265,886 people or 250,065 people per km2
    

In other words DC has less than 2% of Paris's population density. Note, Paris
is a turist destination so many shot's look like DC, but this is the real
city:
[http://i.dailymail.co.uk/i/pix/2015/04/15/17/278DF7CF0000057...](http://i.dailymail.co.uk/i/pix/2015/04/15/17/278DF7CF00000578-3032452-image-m-8_1429115791409.jpg)

~~~
LordKano
DC would have a much greater population density if developers were permitted
to build upwards.

[https://en.wikipedia.org/wiki/Height_of_Buildings_Act_of_191...](https://en.wikipedia.org/wiki/Height_of_Buildings_Act_of_1910)

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chillingeffect
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.

~~~
usrusr
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
> 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
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.

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patmcguire
The article doesn't link to the study. Here it is:

[http://www.pnas.org/content/early/2017/01/01/1611675114.full...](http://www.pnas.org/content/early/2017/01/01/1611675114.full?sid=004341e7-5cb6-4525-be40-4b3fdbcb80e5)

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geofft
Anecdotally, the times I see taxis most crowded/unavailable in New York is in
the East Village / Lower East Side on weekend nights, headed towards the
bridge; my guess is that most of the passengers are drunk and trying to get
home, and I don't particularly want to share a normal-sized car with three
drunk strangers. (Enhancing subway coverage between that area of town and
Brooklyn would help; if someone vomits on a subway, it's easy enough to move
to the end of the car or to the next car.)

Also it's not clear to me if this research assumes that every cab is carrying
a single person. That's often not true, especially for the going-home-from-a-
night-out crowd.

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jwineinger
Pet peeve: how do you "reduce traffic by 3x"? Shouldn't this be "reduce
traffic by 66%"

~~~
ajross
Both of those statements are nonmathematical when parsed strictly, you need a
translation mechanic to turn them into a forumula ("per cent", literally,
doesn't mean a multiplier either). It happens that the percent framing became
common earlier, but when it did it was surely just as ad hoc.

Multiplier framing like that is at least as common, and given that "3" is
easier to understand than "66" (which one has to recognize as the result of
100*(1-(1/3)) for goodness sake!) I genuinely don't understand your peeve
here.

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ebiester
I think America should look into the point to point system that Istanbul
developed (and likely other places) called the dolmuş. These are 10 seat cars
where people split the price to move along one line. (People will usually go
end to end, but can get out along the ride as desired.) The route never
deviates as to provide predictability.

That said, most people take cabs because they don't want to be around other
people -- else, they would take the subway, no?

~~~
geofft
Apart from the subway and bus systems in New York, we have the 10-seat-car-on-
a-fixed-route system too:
[https://en.wikipedia.org/wiki/Dollar_vans_in_the_New_York_me...](https://en.wikipedia.org/wiki/Dollar_vans_in_the_New_York_metropolitan_area)

Most of the time in NYC when I take a cab, it's because there isn't sufficient
subway or bus coverage for the route I want: either I'm going to/from
somewhere deep into Brooklyn or Queens where it's a 10+ minute walk to the
nearest subway (and I'll need at least one transfer once I'm on the subway
system), or I'm trying to take some particular trip across Manhattan that
requires multiple transfers and is much faster by cab. As you'd expect, the
trips that aren't well-served by subway are rare, but they do exist.

~~~
dmix
> The New York City-area dollar van system is highly used, and in 2011, it was
> rated the 20th most used "bus system" in the United States. The dollar van
> and jitney system has been praised as "quietly disruptive" as compared to
> other ride-share services, such as Uber. This has allowed the vans to
> operate without being restricted by the Taxi and Limousine Commission (TLC).

That's very interesting, it fills a void during public worker strikes
spontaneously and ends up being a widely popular service. Thanks for the link.

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blizkreeg
For a while now, I've been wanting to explore single-seating electric commute
pods. At least from my basic analysis, they would be more efficient at moving
people from point A to point B within an urban area.

Cars, imho, are too inefficient a mode of transport for short distances. You
have to make sure they're at capacity to reach 100% utilization.

If anyone is interested in talking more about this or exploring it, I'd love
to hear from you.

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danielharan
Any city building high-throughput transit corridors should take this into
account. I think carpooling and on-demand, self-driven vehicles can help.

Some adjustments might include putting stations _further away_ from each
other, so total travel time decreases. If your last mile is solved by
carpooling, you can go an extra block to get on a train / subway / etc.

Some transit agencies might even consider including these vehicles as part of
their overall offering, especially if that replaces "park and ride". That land
near stations is more valuable when developed with something other than a
parking lot.

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droopyEyelids
I'll continue my little crusade by reminding people that when talking about a
reduction, you should use a fraction or percentage less than 100 for clarity.

For example, this article should have been titled "carpooling apps could
reduce traffic by one third" or "reduce traffic to 1/3 of current levels"

"Reducing something by three times its original amount" is a difficult
sentence to parse correctly, and the linguistically correct interpretation is
almost certainly not what you mean.

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dx034
It would help if NYC would actually encourage not to drive. I was recently
there with 3 people in the car and compared driving & parking in Manhattan vs.
parking outside and taking a train in. In many cities (Amsterdam as an
excellent example), you get cheap, secure parking lots outside of the city
that you can combine with a train/subway ticket. In NYC, this would've been
much more expensive than parking for 3 days.

~~~
InitialLastName
I agree. It would be great if NYC eliminated its free street parking (perhaps
making it residents-only) and priced the rest comparably to parking in
Secaucus.

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zevkirsh
the obsession with number crunching in the transportation space is really
unfortunate because if you just focus on what is going on 'IN THE STREET' ,
you will see that black market transportation already optimizes for
transportation. the problem is that it is not legal, let alone funded for
growth.

there are too many vested special interests,namely, the police, the mass
transit system, the cab drivers, and now, yes, uber and the ride sharing apps
have become part of the institutional dead weight on policy change.

if you want to see what common sense would dictate in ride sharing , it would
be pretty simple.

mini busses would not only be allowed all over new york , anywhere and
everywhere ( because they already run up and down flatbush avenue in brooklyn)
, but large companies would ----if ONLY THEY WERE invited by nyc government
---------flock to build premium versions of minibusses with a minimum of one
entrance per 2 passengers all along the side of the vehicle.

the designs for such a vehicle are plenty. MANY examples of these designs
exist. they are also easily buildable even with safety gear and precautions
built in.

optimizing ride sharing is obvious, you give people vehicles with enough
entrances and enough privacy so that every pair of people can get enter
together, and at most a stranger will be forced to share a pseudo cabin with
one other stranger.

the problem as always IS NOT THE LACK OF MATH AND NUMBER CRUNCHING BY WONKIES
, it is the vested interests that have crushed innovation by having their
meathook money suckers squidlike suffocating government with the help of
willingly crooked politicians.

the same issue plagues all major metropolitan areas in the u.s. , especially
san francisco.

i vote peter theil for dictator of california.

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mwsherman
The article doesn't make the claim in this headline. It makes the claim that
NYC could theoretically have 3x fewer cabs. @dang

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akgerber
While the algorithm is an interesting development, any discussion of 'reducing
traffic' without even acknowledging the concept of induced demand is an
indicator that someone isn't engaging with urban planning remotely seriously.
(hopefully just the person in the PR office?)

~~~
lubesGordi
Do you mean like the increased total number of cars on the road since ride
share has become popular (not sure this is the case, but it seems to be in
dense urban areas where drivers come in from the suburbs)?

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vikiomega9
Link to the paper:
[http://ares.lids.mit.edu/fm/documents/anytime.pdf](http://ares.lids.mit.edu/fm/documents/anytime.pdf)

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EGreg
Parking apps would reduce it by 30%!

Also not shabby eh?

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sctb
We've updated the link from [http://www.theverge.com/2017/1/2/14147286/mit-
research-nyc-t...](http://www.theverge.com/2017/1/2/14147286/mit-research-nyc-
taxi-carpool-uber-lyft), which points to this.

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afian
So happy and proud I know these people - they are amazing!

