Cardiff’s growing network of bike lanes offers more than just places to cycle. Lined with greenery, benches and green-roofed bus shelters, the lanes around the city center seem almost like miniature parks. In a sense, they are.

The Welsh capital city’s new cycle paths are designed to also function as rain gardens — pockets of greenery that, by acting as sponges soaking up heavy rainfall, help prevent flooding. That greenery also provides habitats for wildlife, helps to filter pollutants and offers cooling shade during heat peaks.

This multi-purpose design is a pragmatic response to the current pressures on UK cities and regions to deliver more for less. With the UK economy going through a long period of sluggish growth and the climate-skeptic Reform UK Party overtaking the Conservatives as the main British party of the Right, green policies risk being sidelined if they cannot deliver on multiple goals. While such policies will not convince climate skeptics, their potential efficiency helps counter the narrative that environmental measures cause economic harm.

“It’s challenging delivering these big active travel interventions at a time when public services are being hammered,” says Dan De’Ath, councillor in charge of Climate Change, Strategic Planning and Transport in Cardiff, “but it is part of making cities more functional, it is about the economy. Transport plays such a pivotal role.”

By making these interventions multi-purpose, authorities can also access a wider range of different funding pots. If there is flood mitigation and extra tree cover alongside bike lanes, there’s potentially environmental and health funding available. Following a winter of record rainfall, and the wettest January on record, these decisions have been vindicated.

What’s more, wildlife is moving into this new habitat. In January 2024, an otter appeared in a newly “daylighted” section of canal in the city center, until recently buried beneath slabs of concrete. The resulting footage of the animal eating a fish on a patch of greenery sent a ripple of excitement across the city, reflecting another benefit, says De’Ath. “There is proper hard evidence to show the positive effects psychologically and on general well-being of seeing trees and greenery. It’s proven to have genuine biological benefits, as well as looking nice.”

Cardiff’s initiative was spurred in part by a new law across Wales requiring that so-called sustainable drainage systems (SuDS) be incorporated into any built structures that impact rainfall absorption over an area of 100 square meters (1,076 square feet), including cycle paths.

Wales’ approach is also being adopted in other parts of the UK. Councils in Greater Manchester — including Trafford, Oldham, Stockport and Manchester City — are planting around their cycleways, too, with a citywide ambition that this become a part of everyday transport design.

In Sheffield, the Grey to Green project in the Castlegate area has narrowed a wide road to create new space for walking, cycling and rain gardens, with an adjacent park due to open this year. The project is intended to better connect the area to the city’s core and prevent a recurrence of flooding that inundated the area in 2007. In London, rain gardens that incorporate bird feeders and perches are spreading along cycleways and footpaths in the borough of Waltham Forest, an area that abuts the marshy River Lea.

More broadly, habitat improvements are being adopted across the UK’s National Cycle Network. Current projects include replacing concrete gutters with green drainage channels and soakaways along West Yorkshire’s Spen Valley Greenway, and new wetland features along South Wales’ Swiss Valley route. The Walk Wheel Cycle Trust, which manages the network, is also planting and maintaining trees along paths, not just for shade and greenery, but to prevent soil erosion.

These schemes reflect a growing push to treat “green” and “blue” areas as critical infrastructure because they serve functions (such as cooling and pollution management) that are not just desirable but essential. Proposals to deliver a national Strategic Nature Network — or SNN — want to take this approach countrywide by creating a system of green corridors that would link scattered natural habitats together as one seamless system, expanding tree cover and animal habitats. In Kent’s Blean Woods, for example, where wild bison were reintroduced in 2022, green bridges that allow the bison to cross roads could greatly expand their habitat — with the animals in turn helping to restore the woodlands.

Such a national proposal would build on existing SNNs created at a local level, which have found a variety of funding sources including government, charities and private investors.

Cardiff’s new green bike lanes are not without their growing pains. While the city had a pandemic boom in pop-up cycle routes, it has since focused on improving the temporary routes, rather than expanding the network or connecting missing links. As a result, the city’s overall mileage of protected cycleways has grown by just two miles in two years. Cardiff’s rain gardens made headlines in 2024 when shopkeepers protested the installation of “disgusting” puddle-like rain gardens over former parking spots outside their stores; the puddles were created by people continuing to park there. Residents near a popular park also complained that a new bike track installed there spoiled the space by replacing grass with tarmac.

Still, De’Ath says public opinion is shifting. “When you spoke about this stuff five years ago people would say, ‘oh you’re scaremongering, this is nonsense, it’s just the weather.’” Now, in addition to wetter winters, the UK’s summers are getting hotter — highlighting the need for shade and connected habitats that can protect nature during extreme weather. “It’s been searingly hot and people are like, ‘Oh my god, this is right, we need to do something about it,’” he says. “And had we not been on the front foot already, it would have taken a long time and cost a lot more.”