London, Europe's largest city, is also home to its biggest construction project: Crossrail. Scheduled for completion in 2018, it will cut journey times across the city, dramatically reduce congestion, and is estimated to boost the UK economy by around $67 billion over a 60 year period.
The sheer scale of Crossrail is vast: over 10,000 people are working on the scheme and nine new train stations are being built. Forty two kilometres of rail tunnels are being bored under the city's streets.
"It will be very much a railway of the 21st century," Terry Morgan, Chairman of Crossrail, said in a report for CNBC's Innovation Cities. "It will have brand new trains, brand new stations, and the ability to actually go across London much quicker than you're able to do today."
As well as aiming to dramatically improve the experience of London's commuters come 2018, Crossrail will be well prepared for future challenges, too.
For example, tunnels have been built to accommodate a more frequent service in the future.
"Ours will have the capacity for 12 car train sets in the middle, but we'll buy 10 initially," Morgan said. "We're building in some spare, redundant, capacity that we know we might need at some time in the future, but we don't know when…you only get one chance to build a brand new station in an underground structure."
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As well as improving passenger experience, Crossrail is also backed to boost the British economy, regenerate areas, and bring an extra 1.5 million people to within a forty five minute commute of London.
"This creates growth," Morgan said. "It's really important that, as this economy grows… we insist on ensuring that there's a balance between supporting people in terms of day to day activities but also thinking about what we're going to leave for the next generation, and that's what this project is about."
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While one of London's answer to its future transport challenges is Crossrail, Guangzhou, China, is addressing congestion problems with buses, and lots of them. The Guangzhou bus rapid transit system (BRT) launched in 2010.
A 22.5 km long network solely for buses, it carries around 850,000 passengers daily. The benefits have been extensive: carbon emissions are predicted to fall by 84,000 tonnes per year, journey times have been cut and the cost of travel has fallen.
"It's a big system, it's around 350 buses plus in the peak hour, around one bus every ten seconds," Xiaomei Duan, from Guangzhou BRT, told CNBC. "Before BRT, the road was super-congested…normally, there were four lanes full of buses, it looked like an ocean of buses," she added.
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