Most mayors would be delighted if they could boast that nearly two thirds of the journeys made each day in their cities were done by bicycle. But London’s share is just two per cent; even Copenhagen’s is only 41. The mayor of the Dutch city of Groningen, by contrast, can make this claim. Thanks to a radical urban-planning shift in the 1970s that sidelined four-wheeled vehicles, it has for decades been held up as a model cycle city.

Yet in recent years the dominance of the bike here has thrown up its own challenges. Located near the German border, Groningen is the Netherlands’ major northern economic hub and one of the country’s fastest-growing cities. This has caused more pedestrians, buses and cars (those that are left, at any rate) to battle for space with cyclists in the medieval city centre. Groningen had reached “peak bike” and getting around was becoming unpleasant for everyone. Something had to be done.

“We want to be the most liveable city in Europe and maybe the world,” says vice mayor for transport and traffic Paul de Rook. “That demands that the municipal government make clear choices in the inner city.” And with that typically Dutch combination of pragmatism and creativity, he is tackling the issue head on.

A four-year €85m cycling strategy began in 2015, with interventions ranging from the obvious – more bike parking and cyclist-friendly roundabouts – to the bold. Three new “smart routes” to Groningen University’s bustling Zernike campus will provide dedicated cycle paths to upwards of 20,000 commuters a day, keeping them away from roads and walking routes. Half of a busy ring road skirting the old centre is being given over to bikes to divert them from the crowded centre. Innovative traffic systems at previously deadly crossroads are reducing accidents.

Crucially, though, the plan is not about handing the entire city over to bikes. “It’s not our goal to increase bike-share percentage,” says Alfred Kazemier, the municipality’s director of urban-planning. “Happiness and healthiness are the goal. We believe the next step is walking so we’ve designed everything for the slowest modalities.” Improving life for pedestrians means pavements are getting wider and cyclists are being slowed down on busy streets.

Even with the recent shift in priorities, the car is the biggest loser in all of this, with the municipality aiming to have a zero-emissions city centre by 2025. Those who rely on cars therefore feel (perhaps rightly) aggrieved. To appease them, city hall is focused on providing alternative modes of transport: bike sharing is being added to the city’s six Park and Rides and buses to outer towns run more frequently.

Not everything has worked (such as using geothermal energy to heat bike lanes in winter) and city hall’s four-year plan is ongoing. But Groningen is a unique and intriguing test case for how far a municipality can push cycling before it impacts residents’ mobility and quality of life; and for what you do as city planners when this point arrives. As Kazemier puts it, “We are experimenting a lot here. You have to not be afraid to take some drastic measures.”

Every weekday morning residents of the Mid-Levels in Hong Kong, a hillside neighbourhood perched above the central business district, leave their high-rise flats and descend to work by stepping onto an outdoor escalator. Eighty thousand trips are made daily along this 800m stretch of covered walkways and escalators. Come evening the escalator switches direction for the return commute and tourists flock to see the unique spectacle of workers being ferried up the hill.

The Central-Mid Levels escalator – the longest of its kind in the world – contributes to Hong Kong’s diverse transportation mix, which sees trams, ferries and buses compete with taxis and private cars. But none moves as many people as the mass-transit railway or MTR. About 90 per cent of daily trips in Hong Kong are made by public transport, with close to half by MTR. And this share is only likely to increase as the MTR spreads across the city: since 2016 it has connected all 18 city districts, while several major new lines and extensions are currently under construction.

In essence, the MTR provides a similar service to the outdoor escalator – directly connecting residential high-rises to downtown office buildings. Kowloon Station, which opened in 1998, is a good example.

During morning rush hour the residents of a series of high-rises built above the station descend to the platform by escalator. Passing through a shopping mall, commuters can be at their desks in 15 minutes without stepping outside.

The MTR network has doubled in size since Kowloon Station opened. A fundamental driver of this rapid expansion has been the company’s “rail-plus-property” model: it partners with private developers to build homes, shops, offices and hotels above new stations and thus shares in the higher property values and rental incomes that come with better connectivity; MTR has property interests atop more than half of its 91 stations.

Chunky profits – a record $2.1bn (€1.7bn) last year – fund new lines and upgrades, subsidise already low fares and return dividends to shareholders, the largest of which is the government. Moreover, building mass housing above new lines increases the number of transport customers in a district. “The rail-plus-property model is a way to support urbanisation by sharing the economic benefits that the railway creates,” says Frederick Ma, chairman of the MTR.

Ma is now keen to export the MTR’s model overseas, saying that it “is relevant to growing cities around the world”. To date the MTR has only rolled it out in neighbouring China, where the lay of the land is similar. And admittedly Hong Kong is a special case: seven million relatively wealthy people living on top of each other in high-rises means it’s easier to build railway tracks and tunnels. It also helps that the government owns the majority of greenfield land that it grants to the MTR in return for a lump sum.

The model has also been adopted in Bangkok by BTS Group Holdings, the operator of the city’s elevated Skytrain. But Professor Bo-sin Tang, programme director of urban planning at the University of Hong Kong, says that “to replicate it, cities need to put similar policies and processes in place to Hong Kong and not just hire the best architects or urban planners”. A point worth noting for any city looking to grow upwards rather than sprawl.

Around the world, trams are enjoying a comeback. Detroit brought its trams back in 2017, 60 years after they were ditched; El Paso in Texas is now doing the same. And Jacinda Ardern, New Zealand’s prime minister, has promised a new line in Auckland by 2021 after tramways were abandoned in the 1950s.

Municipalities have in the past been wary of the investment that trams require, opting instead for buses, which are cheaper and more flexible. But trams make sense as part of longer-term strategies and any city planners considering this should look to Zürich. Of the commuters here who use public transport, nearly 60 per cent travel by tram. It’s become both a symbol for the city and a shaper of it, influencing where investment flows.

The tram also holds a special place in the collective psyche. “You can watch the city as you roll by, unlike the subway in other cities where you travel in the dark,” says Roger Mogg, who owns a small business in the town centre. It is also democratic – a place where TV stars rub shoulders with business leaders.

The network, split across 16 routes, covers almost all of the city: lines converge in the centre before travelling out into the suburbs. While this set-up works on a weekday morning, it can lead to bottlenecks in the centre. To tackle this, city hall has invested in some major projects, including the CHF130m (€109m) extension of Line 8 to Hardbrücke Station in the west of the city, which was completed last year. The recently completed Lines 10 and 12, known collectively as the Glattalbahn, are named after the valley they pass through north of the city and serve large mixed-use developments that would have been unthinkable without their tram connections.

Yet the tram network isn’t merely reactive; it can also drive development. According to Andreas Uhl from VBZ, the company that operates central Zürich’s trams, when tramlines were built in the west of the city, “real-estate prices went through the roof”.

But trams are not suited to every city. They wouldn’t be able to carry all 1.5 million people who commute to Manhattan (sometimes passenger flows demand a subway). Yet for a small city like Zürich they’re perfect: democratic, pleasant and quick – well, quick enough.