Nowadays it seems you hardly have to wait five minutes for a
bus in London. But if, like me, you grew up here you'll remember it wasn't
always the case. In the 1990s,
the average speed on the roads of London was slower than it had been at the
beginning of the century, before the motorcar was invented. All that changed in 2003 when the newly
elected mayor, the 'right on' Ken Livingstone, brought in Europe's first urban
congestion charge. The impact on traffic was immediate. But what did it do for
carbon emissions? And should every other city in the world follow in London's
footsteps?
There's been relatively little research into the emissions
impact of urban congestion charging - primarily because surprisingly few such
schemes exist. The world's first congestion charge was introduced in Singapore
in 1975. Then came London. And even more recently, Stockholm introduced its own
charging scheme. Other urban road toll schemes exist but these have been
introduced primarily to raise income rather than cut traffic. And several
cities, particularly in the developing world, run car free days where
vehicles are banned in urban centres. In Jakarta drivers must leave their car
at home once a week!
Residents walk on the roads during Jakarta's weekly car free days |
Congestion charges can reduce emissions in two ways. The
first is obvious. Less cars on the roads means less vehicles emitting CO2.
But in addition less cars means traffic moves faster with less stopping and
starting. And steady
driving is efficient driving.
Transport for London estimated
that the congestion charge reduced the number of cars on London's streets by a colossal
27% between 2002 and 2003 after the charge was introduced. This corresponded to
about 65,000 - 70,000 less journeys. Passenger surveys suggested about half of
these journeys had been transferred to public transport, primarily buses (the
charge was brought in to coincide with a multimillion pound investment in
London's bus network). About 10% switched to other private transport like bikes
and taxis. And a further 35% chose to travel around the congestion charge zone,
or travel at different times of the day. What does this correspond to in
emissions? ... Well, nobody seems to have estimated that.
Unlike us, the Swedes - being the green nation they are -
have estimated the carbon
impact of their scheme. Their charge resulted in a 16% reduction in traffic
over the city centre. And this corresponded to a 14% reduction in emissions.
£100 million was invested in London's buses before the congestion charge was brought in |
So what would happen if every city in the world had a
similar congestion charge? Let's do some back of the envelope calculations. Half the world's population
live in cities so let's assume half the world's billion
cars are in cities too (I'm sure this isn't right - but I searched high and
low for an estimate to no avail. If you know better - put it in the comments
below). The IPCC says
13% of the world's carbon emissions come from transport and (rather lackadaisically)
says 'about
three quarters' of that is from road vehicles. So, do the number crunching
and you'll find that, if every city introduced a congestion charge with the
same impact as Stockholm's, global carbon emissions would be cut by about 0.1%.
It might not sound like a huge amount but there's loads of
other benefits to a congestion charge. It takes less time to get about (vehicle
speeds in London have increased
17% from pre-charging levels). And positive impacts on health have been
reported in both London and Stockholm
due to the decrease in atmospheric concentrations of airborne pollutants and
nitrogen oxides. A King's
College study estimated the congestion charge gave an additional 183 years
of life per 100,000 of the population within the charging zone. Even the
economy, ever the victim of emissions reduction schemes, doesn't seem to have
suffered. A report
by John Lewis found that, although takings had reduced at their central
London stores, there was no measurable effect on central London retail overall.
With stats like these, rolling out congestion charging to every city in the
world seems like a no brainer!