

Data on Beijing Cabs Reveals the Cause of Traffic Jams  - Anon84
http://www.technologyreview.com/communications/38679/

======
GiraffeNecktie
The construction of bigger roads is the CAUSE of traffic jams, not the
solution. The more you improve a highway system, the more people build and
relocate to take advantage of the highway. But you can never upgrade the rest
of the city streets to absorb all the cars spilling off the highway. The only
solution is to invest in mass transit and vigorously control suburban sprawl
(by increasing population density, making downtown living more attractive, and
restricting new development anywhere within driving distance).

~~~
ars
That's not a solution, that's giving up and saying "we won't let you live
there".

My experience is the opposite anyway - the more sprawl the less traffic. Very
congested areas with tons of people were always horrible places to live, never
a place to park, and it takes forever to get anywhere. (And please don't tell
me your "solution" to that is making it so people don't want to go anywhere
because it's too much trouble.)

Putting underground subways like some cities have is simply unfeasible in most
places. Buses are just too slow in congested areas.

~~~
barrkel
If you're living in a very densely populated area and you "never have a place
to park", you're doing it wrong.

(To be clear: what are you parking? The whole point of a densely populated
area is that you don't need a vehicle.)

~~~
ars
But I do need a vehicle - you try going grocery shopping with a bunch of kids
and bringing back 10 or more bags without a car.

I do know there are people who manage it, mainly by shopping almost every day,
or by buying from stores very close to the house (and paying extra and dealing
with a low selection).

But, mass transit is not a complete solution. There are other use cases which
you are not taking into account.

I find very spaced out living, with a car, to be best. Ideally you have a
centralized shopping area, so you only need to make one trip and get
everything. (And of course no houses anywhere near it - keep all the stores
together instead.)

Even better is if the store area is right off the freeway so most of the time
it's on the way to/from the commute. And if not, it's quick to get to.

~~~
Goladus
Sprawl does not mean a spread-out, rural area. Rural areas don't really have
traffic problems in the way that metro areas do. Even suburbs of small cities
don't have traffic problems on the same scale as major cities like NY,
Atlanta, DC, LA, and Chicago. Traffic problems happen in dense, economically
active areas. You have hundreds of thousands of people trying to move through
the region every single day and that is what leads to the traffic jams. Sure,
Kansas City is pleasantly spread out. Driving and parking there is very easy.
But KC is also very small compared to most of the metro areas with serious
traffic problems.

Incidentally, food and grocery selection in the city where I live is vastly
superior. Within a half-mile I have Trader Joes, Whole Foods and a standard
supermarket (which caters to a much more diverse population to begin with) in
addition to a number of specialty and ethnic markets. There's a farmer's
market every Saturday right down the street.

Also in close walking distance: Best Buy, REI, Bed Bath & Beyond, Blick Art
Supplies, several bicycle shops. There's even a store that sells vinyl
records.

I walk to work. I have a car. I use it for groceries sometimes but not often.
I never have a problem finding parking at the supermarket or at home. (parking
anywhere else is dicey, though)

~~~
ars
Were you arguing with me, or helping me make my point? Because I agree with
what you wrote - that's my experience as well. (And where you live sounds just
like where I live.)

~~~
Goladus
Neither, really. Though I might not have been clear-- I live in a densely
populated area where there's public transit and I don't use a car much. I grew
up in rural areas where the spread-out method works better.

What doesn't work is trying to solve traffic problems by spreading everything
out. In places that already are spread out, there really isn't a traffic
problem to solve and communities can decide whether they want mixed-use
environments or segregated environments based on other factors. In places
where you already have a critical density (like Eastern MA where I live),
spreading things out is no more feasible than a subway in rural Ohio. Right
now, trying to drive from Cambridge to Waltham at 6:00pm will probably take
45-60 minutes due to traffic congestion. That's because of all the people
trying to leave Boston for the suburbs.

------
Goladus
_"I think this is an interesting direction, though I wonder to what extent the
real problem in urban planning is not having the resources—money—to do
anything about it," says Sam Madden, an associate professor at the MIT
Computer Science and Artificial Intelligence Laboratory who studies wireless
sensor networks, including GPS units._

Resources-- and political will. It doesn't matter what your data shows if the
residents won't let you build roads through their neighborhoods. In Cambridge,
MA there are roads that actually already exist but rush hour traffic is
deliberately blocked from using them. (eg Whitemore ave / Seagrave Road
between Alewife Brook Parkway and Mass Ave)

~~~
PakG1
It's like that thread about the guy who ran simulations to figure out the
optimal way to board planes. Even if it's true, not gonna happen, 1st class
pay partly for the right to board first. Exactly the same type of situation.

~~~
dspillett
First class can still board before the rest of us in steerage in that case
though.

First class on in what-ever order is most efficient for that part of the
cabin, then the rest on in what-ever order is best for those areas.

Though what would really happen would be "first class on in what-ever order
they fight for amongst themselves because they all consider themselves too
important to listen to instructions from the boarding staff" followed by "the
rest on in what-ever order they fight out as they don't care about the common
good if that means they are on 12th instead of 1st".

------
jinushaun
I was looking for a conclusion, but couldn't seem to find it. Anyone? The
closest thing I can find is that going from A to C clogs up B, so city
planners should create a direct A to C route.

~~~
astine
The clever bit is that they are using taxi routes to predict traffic patterns
rather than just looking at where the traffic jams happen. They've
demonstrated that creating direct routes which correspond to taxi routes does
much to alleviate congestion.

------
jahmed
Traffic is the result of incorrect pricing. Its cheap to drive relative to the
alternatives taking into account all non-tangible benefits like privacy and
comfort or the lack of a schedule and predefined route. If it is more
expensive to drive people will drive less. You can use good pricing to
influence behavior. If you charged everyone getting on an Los Angeles metro
area freeway $5 between 7-9am and 2-5pm Monday-Friday some people wouldnt use
the freeways. Yes now they are tollways but they are already tollways only
funded through taxes. Really this wouldnt be a great idea because most people
will just drive on the streets resulting in a shift in traffic but probably
not a significant decline in total traffic. To be more effective this need to
be combined with a robust mass transit network. When gasoline prices spiked in
California people started driving less but overall there wasnt a significant
change in demand mainly because of the lack of viable substitute.

What needs to happen is a combined approach of dynamic pricing of driving and
public transit along with investment in the transportation system as a system
and good urban planning. Without a combined approach problems appear
intractable but only because the incentives just are misaligned.

------
malandrew
The problem in Beijing is painfully obvious if you've ever experienced the
traffic jams there. The main cause of the jams other than cars is badly
designed on-ramps and off-ramps onto the ring roads.

Beijing has a very unique on-ramp/off-ramp solution that I have yet to
encounter in any other city. When they were first designed and put into use
they made a lot of sense. A friend of mine who has lived in the city since
1999, said that back in the day there were almost no cars on the road and huge
avenues. The on-ramps and off-ramps were designed and put into place at around
this time.

The problem with the ramps is the the on-ramp leads onto the ring road and
about 100m later there is an off-ramp. Once the traffic gets really bad the
exiting traffic blocks the flow of the entering traffic. Once that happens the
entire city comes to a stop because this on-ramp/off-ramp problem cascades
throughout the city and everywhere becomes blocked.

~~~
enf
That sounds like a cloverleaf interchange... Once a very popular choice to
build because it only requires building one bridge, now less common because of
that problem and because they use land very inefficiently.

------
ohashi
Speaking of cabs in Beijing: how come I can never get one? I see empty cabs
drive by constantly (and not just foreigners, locals too). Or they sit around
not wanting to pickup fares. The whole cab system seemed broken when they
didn't want to drive people places. Anyone have any idea what sort of
incentive system these guys have or try and explain this behavior?

------
stanleydrew
Single page printable version:

[http://www.technologyreview.com/printer_friendly_article.asp...](http://www.technologyreview.com/printer_friendly_article.aspx?id=38679)

------
JoeAltmaier
Combine with OnStar's ubiquitous capture of private car driving, and maybe we
already have the data in America?

