How to solve traffic jams Jonas Eliasson

hi I’m here to talk about congestion

namely road congestion road congestion

is a pervasive phenomena the existing

basically all of the cities all around

the world which is a little bit

surprising when you think about it I

mean think about how different cities

are actually I mean you have the typical

European cities with a dense urban core

good public transportation mostly not a

lot of Road capacity but then on the

other hand you have the American cities

it’s moving by itself okay

anyway the Americans say this lots of

roads dispersed to the large areas

almost no public transportation and then

you have the emerging world cities with

a mixed variety of vehicles mixed

land-use patterns also rather dispersed

but often with a very dense urban core

and traffic plan is all around the world

has tried lots of different measures

densities or dispersed stages lots of

roads or lots of public transport or

lots of bike lanes or more information

or lots of different things but nothing

seems to work but all of these attempts

have one thing in common they’re

basically attempts at figuring out what

people should do instead the rush-hour

car driving they’re essentially two

point attempts at planning what other

people should do planning their life for

them now planning complex social system

is a very hard thing to do and let me

tell you a story back in 1999 when the

Berlin Wall fell an urban planner in

London got a phone call from a colleague

in Moscow saying basic him hi this is

Vladimir I’d like to know who’s in

charge of London’s bread supply and the

urban plan was what do you mean who’s in

charge children’s I mean no one is in

charge oh but surely someone must be in

charge I mean it’s a very complicated

system someone must control all of this

no no no one is in charge I mean it

basically our haven’t through the fault

of it I mean it basically organizes

itself it organizes itself

that’s an example of a complex social

system which has the ability of

self-organizing and this is a very deep

insight when you try to solve really

complex social problems the right thing

to do is most of the time to create

incentives you don’t plan the details

and people will fight you figure out how

what to do how to adapt to this new

framework and let’s now look at this how

do we can we can use this insight to

combat road congestion

this is map of stock of my hometown now

Stockholm is a medium-sized city roughly

2 million people but Giacomo’s has lots

of water and lots of water means lots of

bridges narrow bridges old bridges which

means lots of road congestion these red

dots show the most congested parts which

other bridges that lead into the inner

city and then come what someone came up

with the idea that apart from good

public transport or import the support

from spending money on roads let’s try

to charge drivers one or two euros at

these bottlenecks now one or two use

that isn’t really a lot of money I mean

compared to parking charges andronica

cetera so you would probably expect that

car drivers wouldn’t really react to

this fairly small charge you would be

wrong

1 or 2 euros was enough to make 20

percent of course disappear from rush

hours now 20 percent well that’s a

fairly huge figure you might think but

you still get 80 percent left of the

problem right because you still have 80

percent of traffic now that’s also wrong

because traffic happens to be a

nonlinear phenomenon meaning that once

you reach above a certain capacity

threshold then congestion starts to

increase really real rapidly but

fortunately it also works the other way

around if you can reduce traffic even

somewhat then congestion will go down

much faster than you might think

now congestion charges were introduced

in Stockholm in the Dom On January 3rd

2006 and the first picture here is the

picture of Stockholm one of the typical

streets January 2nd the first day with

the congestion charges looked like this

this is what happens when you take away

20% of the cars from the streets you

really reduce congestion quite

substantially but well as I said I mean

car drivers adapt right so after a while

they would all come back because they

sort of get gotten used to the charges

wrong again it’s now six and a half

years ago since the congestion charge

bring to doose’s calm and we basically

have the same low traffic levels still

but

see there’s an interesting gap here in

the time series in 2007 well the thing

is that the congestion charges they were

introduced first as a trial so they were

introduced in January and then abolished

again in a at the end of July followed

by a referendum and then they were

reintroduced again in 2007 which of

course was the wonderful scientific

opportunity I mean this was really it

was a really fun experiment to start

with and we actually got to do it twice

and person I’d like to do this every

once a year or so but they wouldn’t let

me do that so but it was fun anyway

so we followed we followed up what

happened this is the last day with the

congestion charges July 31st and you see

the same street but now it’s summer in

summer in Stockholm is a very nice and

light time of the year and the first day

went without the congestion charges look

like this all the cars were back again

and you even have to admire the car

drivers they adapt to extremely quickly

the first day they all came back and

this effect and this effect hang on

so 2007 figures look like this now these

traffic figures are really exciting and

a little bit surprising and very useful

to know but I would say that the most

surprising slide here I’m going to show

today is not this one it’s this one this

shows public support for congestion

pricing in Stockholm and you see that

when congestion pricing were introduced

in well beginning of spring 2006 people

were fiercely against it seventy percent

of the population who didn’t want this

but what happened when the congestion

charge was there it’s not what you would

expect that people hated it more and

more no on the contrary they changed up

to a point where we now have seventy

percent support for keeping the charges

meaning that I mean let me repeat that

seventy percent of the population in

Stockholm want to keep the price for

something that used to be free okay so

why can’t that be why is that well think

about it this way

who changed I mean the 20% of the car

drivers that disappeared surely they

must be discontent in a way and where

did they go if we cannot just understand

this then maybe we can figure out how

people can be so happy with this well so

we did this huge interview survey with

lots of travel service and try to figure

out who changed and where did they go

and turned out that they don’t know

for some reason the car drivers are they

are confident they actually drive the

same way that they used to do and why is

that it’s because the travel patterns

are much less stable than you might

think each day people make new decisions

and people change and the world changes

around them and each day all of these

decisions are sort of nudged ever so

slightly away from rush hour car driving

in a way that people don’t even notice

they’re not even aware of this

themselves

and the other question that who changed

their mind who changed their opinion and

why so we did another interview servant

tried to figure out why people change

their mind and who would put type of

group change their mind and after

analyzing the answers it turned out that

more than half of them believe that they

haven’t changed their minds they are

actually confident that they have they

have like congestion pricing all along

which means that we are now in a

position where we have reduced traffic

across this tall cordon with 20% and

reduced congestion by enormous numbers

and people aren’t even aware that they

have changed and if they honestly

believe that they have liked this all

along this is the power of nudges when

trying to solve complex social problem

and when you do that

you shouldn’t try to tell people how to

adapt

you should just nudge them in the right

direction and if you do it right people

will actually embrace the change and if

you do it right people will actually

even like it thank you

you