Taking an Uber or Lyft just makes everything worse

Here’s a question: is it better to drive somewhere or to take a
ride-hailing service like Uber or Lyft?


I don’t mean better for you personally — faster or cheaper. I
mean better for the world, for society, for the air and
atmosphere … better, all things considered.


A clever new study from researchers at Carnegie Mellon University
attempts to answer that question.


Ride-hailing services carry more external costs than private
vehicles


In the paper, Jacob Ward, Jeremy Michalek, and Constantine
Samaras attempt to tally up the relative costs to the environment
and society of taking a trip via a privately owned vehicle vs.
taking the same trip in what they call a transportation network
company (TNC) like Uber or Lyft, in six of the companies’ biggest
markets.


This involves two steps in each market. First, they add up how
many miles the respective vehicles travel per trip. Then, they
add up the total externalities — in vehicle emissions,
congestion, crashes, and noise — represented by each mile
traveled. (These externalities, notoriously, are not priced into
transportation decisions; thus the name.)


To understand the results, you have to understand one key fact:
TNC vehicles travel more miles per trip. They have to drive
between where they drop off one fare and pick up another, which
sometimes involves quite a bit of just wandering around. This
time spent with no passenger is called “deadheading,” and those
miles must be added to their trip miles.


Here’s a clear visual representation:


Those dotted black lines on the bottom half? That’s deadheading.


Those extra miles traveled represent more externalities — more
cost to the environment and society. On average, a TNC trip
carries 32 to 37 cents more in external costs than a private
vehicle trip. (See also this recent MIT study, which found that
TNC vehicles increase urban road congestion.)


There are three countervailing factors, but only the third is big
enough to flip the equation enough to give TNCs the advantage in
some limited circumstances.


Ride-hailing services reduce air pollution


First, though additional miles lead to more greenhouse gas
emissions, congestion, crashes, and noise, somewhat
counterintuitively, they lead to less air pollution. The secret
here is that the bulk of particulate air pollution is generated
from “cold starts,” i.e., engines turning over to start up. By
contrast, TNC vehicles arrive “hot.” Their engines are already
running, so they don’t do cold starts. In addition, TNC vehicles
are, on average, newer, and thus cleaner.


On average, TNC trips represent a 50 to 60 percent decline (9–13¢
per trip) in air pollutants like NOx, PM2.5, and VOCs.


If TNC vehicles electrify faster than private vehicles, that
advantage will grow, because EVs generate no tailpipe pollution.
But if private vehicles electrify equally fast, the comparative
advantage will stay the same.


Regardless, the difference is not enough to overcome the other
externalities. TNC trips represent a 20 percent increase in costs
from greenhouse gas emissions and a 60 percent increase in costs
from congestion, crashes, and noise (all told, about 45¢ more per
trip).


Overall, a 9–13¢ decrease and a 45¢ increase add up to 32 to 37
cents more per trip, on average.


Electric ride-hailing vehicles … are still mostly worse than
private vehicles


The second countervailing factor is vehicle electrification.
Doesn’t that reduce externalities? What the researchers found is
that a) if the TNC car is electric, while b) the private vehicle
alternative is an internal combustion engine car, and c) the TNC
car charges entirely with zero-carbon electricity, then the
overall environmental and social costs of a TNC trip and a
personal vehicle trip are … about the same.


Of course, those conditions are rarely met. On real-world grids,
which are still powered overwhelmingly by fossil fuels,
electrification of TNCs reduces the relative advantage of
personal vehicle trips by about 16 or 17 percent. It does not
eliminate the advantage. And of course, that advantage will
shrink as the private vehicle fleet electrifies.


So what, then, is the third countervailing factor, the one that
can actually make a TNC trip better than a personal vehicle trip?


Shared ride-hailing vehicles are better than private vehicles


Maybe you’ve already guessed the answer: it’s ride-sharing. Put
two people in the TNC car — i.e., have one TNC trip substitute
for two personal vehicle trips — and voilà, you flip the script
and your TNC trip is a net positive for the world. “When a TNC
trip is known to be pooled,” the paper says, “shifting travel
from a private vehicle reduces net external costs by a mean value
of $0.60/trip.”


Wow, if you pooled three people you could save even more. Or four
people. You could even pool dozens of people on large vehicles
that travel on fixed routes and timetables. You could reduce all
kinds of externalities! I wonder if anyone has tried that.


Speaking of which, what if the TNC trip displaced a trip on
public transit, where the marginal cost in externalities of an
additional passenger is effectively zero? What if it displaced a
trip done via walking or biking, where the marginal externalities
are, again, zero?


The study looked at that too: “When TNCs displace transit,
walking, or biking, rather than personal vehicles, the increase
in externalities is about three times larger (+$1.20/trip).”


What about avoided vehicle purchases?


You might think that, with the easy availability of TNCs, it
might be possible for fewer people to buy cars, which would count
on the positive side of the ledger.


However, there’s no such comfort. I asked the authors about this
and it turns out they did another study (out on Jan. 6, d’oh)
which found that the arrival of Uber and Lyft to a market tends
to be correlated with a small increase in car ownership,
especially in places where car ownership is already high and
there’s not much population growth.


Via email, Michalek adds:


Even if Uber/Lyft do cause a reduction in vehicle ownership in
some cities, I don’t think that alone would change our analysis
about the costs and benefits of ridesourcing to society very
much, because vehicle production emissions are a small part of
overall lifecycle costs. The main costs come from driving.


What could change our results is if Uber/Lyft enable travelers to
walk and use transit more than they would have otherwise. This
could be, for example, (1) because Uber/Lyft enable a traveler to
get to a transit line (providing a first mile / last mile
solution); (2) because Uber/Lyft can fill in gaps in transit
services, allowing travelers to take the train out to a nightlife
area and take an Uber home after the trains stop running; or (3)
because not owning a vehicle forces the traveler to walk,
carpool, and use transit more often than they would if they had a
convenient personal car option.


Unfortunately, there’s not a ton of evidence for TNCs enabling
more transit trips either. Reviewing the studies done to date on
the impact of TNCs on transit, the paper concludes:


We also find no statistically significant average effect of TNC
entry on fuel economy or transit use, but find evidence of
heterogeneity in these effects across urban areas, including
larger transit ridership reductions after TNC entry in areas with
higher income and more childless households.


There’s no way to avoid the conclusion: in most places, in
current circumstances, all things considered, it’s worse to take
a TNC ride than to drive a private vehicle.


What all of this means


I hope the implications of this research are obvious: ban cars.


Ha ha, I’m kidding. Kind of. But Uber and Lyft aren’t helping
anything. They’re making most things worse. Even if they
electrify, they’re still mostly making things worse.


The most notable finding in this latest study is something we
already knew: moving people out of private vehicles (whether
they’re driving or not) into walking, biking, and public transit
sharply reduces overall costs to society and the environment. The
difference that shift makes swamps any differences between the
types of private vehicles we choose.


The basic problem with cars — whether they’re private, TNCs,
taxis, flying cars, underground cars, or autonomous Personal Air
Land Vehicles (PAL-Vs) with 5G and lasers — is a simple matter of
geometry: they take up lots of space.


You can not have thousands of people living close together, each
with their own two-ton vehicle, without congestion, sprawl,
noise, crashes, air pollution, climate change, and all the rest
of the horrors cars bring. That’s true of big cities, but it’s
also true of small towns. If everyone has their own vehicle,
there’s going to be traffic congestion or sprawl or both.


The only way to tackle all of these externalities at once is to
get people out of cars. Out of their own cars, out of the Ubers.


That means prioritizing multimodal transportation in
infrastructure and spending decisions. Creating protected walking
and biking corridors that connect across town. Reclaiming lanes
and whole streets from cars and turning them over to transit or
simply to neighborhood walking and gathering. Upzoning and
increasing density, especially around transit stops. Subsidizing
electric bikes. (Basically, doing what Barcelona and Paris are
doing.)


Electrifying vehicles will help on climate change, especially as
the grid gets cleaner, but it’s not a solution to cars. Fancy new
kinds of cars, even if they fly or go through tunnels or run on
unicorn farts, are not a solution. Apps are not a solution.


The only solution to the problem of cars is fewer cars. That
should be the goal of policy — not just transportation policy,
but land-use policy and urban policy and economic policy and
climate policy. For those who care about the public good, Uber
and Lyft are a distraction.


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