Are road diets the next big thing for US cities?

Does Chicago really need all those lanes? Image: Getty.

Like so many new concepts in urban planning, road diets seem like a great idea at first. And, like so many concepts in urban planning, they tend to generate a lot more criticism once they’re put into place.

The idea of a road diet is simple: to pinpoint streets that have excess capacity and could be narrowed down without significant car congestion, so providing space for other uses, such as sidewalks and bike paths.

It’s also an almost exclusively American concept, which makes sense; while streets in Britain and other European countries aren’t exactly crying out to be narrowed down, on the other side of the Atlantic, the streets seem to be the only thing wider than the country’s waistlines.

The roots of the concept date back to the 1970s, but it only began gaining traction over the past decade, loosely connected with other movements such as smart growth and complete streets.


Planners in the US began studying cases in which city streets had been widened to improve traffic flow for cars. They found that, in most cases, these projects did little to improve traffic flow, while creating an enormous increase in accidents. For instance, a study done in Fort Madison, Iowa, showed that while widening a main road led to a traffic volume increase of 4 per cent, it also increased the accident rate 14 per cent, and the injury rate by 88 per cent.

The obvious response to these findings is, naturally, to slim wider streets back down. But this slimming down can take many forms: widened sidewalks; replacing four-lane highways with three-lane ones, in which the middle lane is for those turning; and separated bike lanes. Last year, urban planner and author Jeff Speck teamed up with animation specialist Spencer Boomhower to create a series of videos showing the many possible forms road diets can take.

How effective has the concept been? In the US, road diets have seen a number of success stories. In New York City, a 2013 study revealed that road diets there had “significant safety benefits”.  They’ve seen success on the west coast, too: a pioneer in road diets, San Francisco has implemented 34 road diet projects over the last four decades, with favourable reactions from traffic engineers. Similar projects have also been implemented successfully in nearby Davis, California.

A street in Davis, CA, before its road diet. Image: Transport Observer/Wikimedia Commons.

But though road diets have allowed some cities to slim down their traffic safety problems, others have found that sticking to road diets is harder than sticking to actual diets.

Take Carolina Beach, North Carolina. Back in 2010, planners implemented a road diet on Lake Park Boulevard, one of the city’s main thoroughfares, in a bid to make the city more bike friendly.

But the measure was met by howls of protest. Local businesses complained of decreased sales, and the city’s car traffic during holidays led to increased traffic jams. In 2012, the road diet was reversed.  

Down the coast, in Gainesville, Florida, a road diet was adopted in mid-2013 for a wooded stretch of 8th Avenue. Four traffic lanes were reduced to two on a trial basis.

While the trial decreased injuries significantly, it met with staunch criticism from drivers, inconvenienced by a difficult merge area created by the road diet. The new configuration remained for over a year, but it was finally removed after being voted down by the city commission in December 2014, though plans are in the works for adding a shared pedestrian/cycle path on both sides of the road.

The same street after its road diet. Image: Transport Observer/Wikimedia Commons.

Then there’s Los Angeles, which despite some noble efforts to reverse its car-centric status by expanding its metro system, lives up to its reputation in its efforts to pursue road diets. Back in 2011, an attempt to implement a road diet on Wilbur Avenue, deep in the depths of the suburban San Fernando Valley, was quickly put to sleep after massive neighbourhood outcry.

Even in Silver Lake, an LA neighbourhood packed with bike-loving hipsters, the policy is in trouble. A road diet on Rowena Avenue in place since 2013 has been the source of continuous controversy, including angry driver rants caught on tape, though it remains in place for the time being.


Though the reasons road diets fail vary city by city, their common underlying cause boils down to political convenience. By their nature, road diets create an immediate inconvenience for drivers – who tend to be more affluent and politically connected; to compensate that, there’s only the long-term promise of creating greater safety, and a more bike and pedestrian friendly urban environment. For local politicians eager for quick victories, this all too often proves to be a toxic combination.

The lesson is clear. Road diets have paid off for some US cities. But for others, powerful political forces and a deeply rooted car culture have made sticking to road diets as difficult as swearing off junk food.

 
 
 
 

Here’s how we plant 2 billion more trees in the UK

A tree in Northallerton, North Yorkshire. Image: Getty.

The UK’s official climate advisor, the Committee on Climate Change (CCC), recently published a report outlining how to reduce the 12 per cent of greenhouse gas emissions that come from land use by two thirds by 2050. Alongside recommending cutting meat and dairy consumption by 20 per cent, the report calls for the annual creation of up to 50,000 hectares of broadleaf and conifer woodland for the next three decades. This would increase forest cover from 13 per cent to at least 17 per cent – a level not seen in Britain since before the Norman invasion.

Reforestation at that rate would mean creating roughly the area of the city of Leeds every year for the next three decades. At typical stocking densities of 1,500 stems per hectare, the ambition is to establish some 2.25 billion additional trees. Given that the UK, as with most of Europe, is in the grip of ash dieback, a disease likely to prove fatal for many millions of native ash trees, the scale of the challenge is massive.

On a crowded and intensively farmed island like Britain, unlocking a million and a half hectares of land will be no mean feat. But it’s not impossible – and is an unprecedented opportunity not only to tackle the climate crisis but also the biodiversity crisis that is every bit as detrimental to our wellbeing.

Trees and farms

One million and a half hectares is just 6 per cent of the mainland UK’s land area. To give some sense of perspective on this, 696,000 hectares of “temporary grassland” were registered in 2019. So if land supply is not the problem, what is? Often it’s cultural inertia. Farmers are firmly rooted to the land and perhaps understandably reluctant to stop producing food and instead become foresters. But the choice need not be so binary.

The intensification of agriculture has caused catastrophic declines in many species throughout the UK by reducing vast wooded areas and thousands of miles of hedgerows to small pockets of vegetation, isolating populations and making them more vulnerable to extinction.

Integrating trees with the farmed landscape delivers multiple benefits for farms and the environment. Reforestation doesn’t have to mean a return to the ecologically and culturally inappropriate single-species blocks of non-native conifers, which were planted en masse in the 1970s and 1980s. Incentivised under tax breaks to secure a domestic timber supply, many of the resulting plantations were located in places difficult or in some cases impossible to actually harvest.

Productive farmland needn’t be converted to woodland. Instead, that 4 per cent of land could be found by scattering trees more widely. After all, more trees on farmland is good for business. They prevent soil erosion and the run-off of pollutants, provide shade and shelter for livestock, a useful source of renewable fuel and year-round forage for pollinating insects.

The first tranche of tree planting could involve new hedgerows full of large trees, preferably with wide headlands of permanently untilled soils, providing further wildlife refuge.


Natural regeneration

Where appropriate, new woody habitats can be created simply by stopping how the land is currently used, such as by removing livestock. This process can be helped by scattering seeds in areas where seed sources are low. But patience is a virtue. If people can learn to tolerate less clipped and manicured landscapes, nature can run its own course.

A focus on deliberate tree planting also raises uncomfortable truths. Most trees are planted with an accompanying stake to keep them upright and a plastic shelter that protects the sapling from grazing damage. All too often, these shelters aren’t retrieved. Left to the elements, they break down into ever smaller pieces, and can be swept into rivers and eventually the ocean, where they threaten marine wildlife. Two billion tree shelters is a lot of plastic.

The main reason for using tree shelters at all is because the deer population in the UK is so high that in many places, it is all but impossible to establish new trees. This also has serious implications for existing woodland, which is prevented from naturally regenerating. In time, these trees will age and die, threatening the loss of the woodland itself. Climate change, pests and pathogens and the lack of a coordinated, centrally supported approach to deer management means the outlook for the UK’s existing treescape is uncertain at best.

An ecologically joined-up solution would be to reintroduce the natural predators of deer, such as lynx, wolves, and bears. Whether rewilding should get that far in the UK is still the subject of debate. Before that, perhaps the focus should be on providing the necessary habitat, rich in native trees.

A positive response would be to implement the balanced recommendations, made almost a decade ago in a government review, of creating more new habitat, improving what’s already there, and finding ways to link it together. Bigger, better, and more connected habitats.

But the UK is losing trees at increasing rates and not just through diseases. The recent removal of Victorian-era street trees in Sheffield and many other towns and cities is another issue to contend with. As the climate warms, increasing urban temperatures will mean cities need shade from street trees more than ever.

Trees aren’t the environmental panacea that the politicians might have people believe – even if they do make for great photo opportunities – but we do need more of them. Efforts to expand tree cover are underway across the world and the UK will benefit from contributing its share. Hitting the right balance – some commercial forestry, lots of new native woodland and millions of scattered trees – will be key to maximising the benefits they bring.

Nick Atkinson, Senior Lecturer in Ecology & Conservation, Nottingham Trent University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.