Does cutting speed limits to 20mph actually work?

20’s plenty. Image: educators.co.uk/Flickr/creative commons.

A new speed limit of 20mph has been proposed for roads in central London. The plans, which would reduce the limit to 20mph within the Congestion Charging Zone, are part of the “Vision Zero” strategy, which aims to “eliminate deaths and serious injuries from London’s transport network by 2041”.

The main reason for reducing traffic speed is to lessen the likelihood of a collision – and to reduce the severity of road traffic casualties. Research indicates that if a pedestrian is struck by a vehicle at 24mph, they have a 10 per cent risk of dying. This goes up to 25 per cent at 32mph, and 50 per cent at 41mph. A reduction in speed of as little as 1mph is associated with a reduction in casualties of up to 6 per cent.

Yet plans for the 20mph limit in London have been controversial. Some question the impact it will have on increased traffic congestion and air pollution. Retailers are concerned it will discourage customers from visiting the city centre due to increased congestion. Others question the need for a 20mph limit in areas where congestion means it is rarely possible to go any faster than that. So what’s the evidence on 20mph limits so far?

Many look to the example of Bristol to support the introduction of 20mph limits. Headline findings have so far suggested that “four lives a year are saved” in the city, which reduced speeds in 2014 and 2015. It has also been estimated that Bristol has saved over £15m per year due to lower casualty rates.

Elsewhere, results from pilot schemes in Edinburgh and Portsmouth indicated an overall reduction in speed of between 0.9mph and 1.9mph on roads where 20mph limits were implemented. In Portsmouth, an average reduction of 6.3mph was seen on roads that were characterised by speeds of over 24mph before the lower limits were introduced. The city also showed a 22 per cent reduction in reported road casualties where 20mph maximums had been introduced.

The pilot research has also indicated that 20mph limits in Bristol and Edinburgh have led to increases in people choosing to walk (up to 10 per cent) or cycle (up to 5 per cent). Other studies have shown increases in perceived road safety, and the pleasantness of residential environments.

But others are more swayed by what has happened in Manchester, where the supposed benefits of 20mph limits have been questioned. There, a drop in the number of accidents in 20mph zones was not as great as it was on some faster roads. In light of these findings, Manchester City Council reviewed their 20mph scheme and withdrew funding.

An overall review of previous research concluded that 20mph schemes can reduce accidents, injuries and traffic volume, and improve perceptions of safety, while being cost effective. However, of the ten studies included in the review, only two focused specifically on speed limits (use of 20mph signage without physical interventions such as speed bumps).

The review also found a lack of evidence assessing the impact of such schemes on addressing social inequalities – road casualties are higher in the most deprived areas.

What is less clear are the potential risks of implementing such schemes, particularly for noise and air pollution. Some argue that lowering traffic speed will lead to increased congestion and consequently increased air pollution. On the other hand, if 20mph speed limits are successful in encouraging more sustainable travel modes then this will result in a reduction in air pollution.

The evidence to date is somewhat limited because of a lack of robust, long-term evaluations. In particular, there has not been enough investigation into their economic impact and cost effectiveness.

Looking at the signs

So what can London learn from the evidence so far? The first lesson is that communication is key – it is vital the public is kept up to date with plans. It is also important to have an evaluation plan which includes interim analyses, so that any changes made are based on solid evidence.


And that evaluation should be a broad one. As well as measuring changes in traffic speed, and the number and severity of collisions, include other measures such as changes in behaviour when it comes to travel mode and liveability.

In our increasingly congested cities, more must be done to move towards sustainable modes of travel – and for society as a whole to become less reliant on cars. However, changing social norms will take time, and in order to be successful, local authorities must ensure they engage with the general public when implementing ambitious transport plans.

London is the latest city in an ever growing list to implement 20mph speed limits. At the “Is 20mph plenty for health?” research team, we would encourage London to learn lessons from the other cities – and to share its knowledge as we continue to build the evidence base for 20mph speed limits.

The Conversation

Ruth Hunter, Lecturer, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast.

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

 
 
 
 

In South Africa's cities, evictions are happening despite a national ban

An aerial view shows a destroyed house in Lawley, south of Johannesburg, on April 20, 2020. The city has been demolishing informal structures on vacant land despite a moratorium on evictions. (Marco Longari/AFP via Getty Images)

On the morning of 15 July, a South African High Court judge ruled that the city of Cape Town’s Anti-Land Invasion Unit had illegally evicted a man when it destroyed the shack where he was living.

That afternoon, the Anti-Land Invasion Unit was out again, removing shacks in another informal settlement.

Evictions were banned in South Africa for nine weeks, after the national government placed the country under a strict Covid-19 lockdown in late March. At present, eviction orders are automatically suspended until the country moves to a lower “alert level” and can only be carried out with a special order from a judge.

Yet major cities including Cape Town, Johannesburg and eThekwini (created through the merger of Durban with several surrounding communities), have continued to use municipal law enforcement agencies and private security companies to remove people from informal housing. In many cases those operations have been conducted without a court order – something required under regular South African law.

Around 900 people were evicted from three informal settlements in eThekwini during the eviction ban, according to the Church Land Programme, a local NGO. Its director, Graham Philpott, says it’s also aware of evictions in other informal settlements.

While evictions aren’t a “new experience” in these communities, the NGO released a report on lockdown evictions because they were “so explicitly illegal”. “There was a moratorium in place,” Philpott says, “and the local municipality acted quite flagrantly against it. There’s no confusion, there’s no doubt whatsoever, it is illegal. But it is part of a trend where the eThekwini municipality has acted illegally in evicting the poor from informal settlements.”

Evictions also took place in Cape Town and Johannesburg during so-called “hard lockdown” according to local activists. In eThekwini and other municipalities, the evictions have continued despite restrictions. In Cape Town, authorities pulled a naked man, Bulelani Qholani, from his shack. That incident, which was captured on video, drew condemnation from the national government and four members of the Anti-Land Invasion unit were suspended. 


The cities say they’re fighting “land invasions” – illegal occupations without permission from the land owner.

“Land invasions derail housing and service projects, lead to the pollution of waterways, severely prejudice deserving housing beneficiaries and cause property owners to lose their investments over night,” Cape Town’s executive mayor, Dan Plato said in a statement. (Plato has also claimed that Qholani did not live in the shack he was pulled from and that he disrobed when municipal authorities arrived.)

South African municipalities often claim that the shacks they destroy are unoccupied. 

If they were occupied, says Msawakhe Mayisela, a spokesman for the eThekwini municipality, the city would get a court order before conducting an eviction. “Everything we’re doing is within the ambit of the law,” Mayisela says. But “rogue elements” are taking advantage of Covid-19, he added.

“We fully understand that people are desperately in need of land, but the number of people that are flocking to the cities is too much, the city won’t be able to provide housing or accommodation for everyone overnight,” he says. 

While eThekwini claims to be a caring city, local activists say the evictions show otherwise.

In one case, 29 women were evicted from shacks during the hard lockdown. With nowhere to go, they slept in an open field and were arrested by the South African Police Service for violating the lockdown, Philpott says.

“These evictions are dehumanizing people whose dignity is already compromised in many ways,” says S’bu Zikode, the president of Abahlali baseMjondolo, a community organization whose Zulu name translates to “the people of the shacks”. 

“It has reminded us that we are the people that do not count in our society.”

Municipal law enforcement and private security contractors hired by cities regularly fire rubber bullets, or even live ammunition, at residents during evictions. Some 18 Abahlali baseMjondolo activists have been killed since the organization was founded in 2005, Zikode says, most by the eThekwini Land Invasion Unit and Metro Police.

(Mayisela says that if city employees have broken the law, Abahlali baseMjondolo can file a complaint with the police. “There is no conclusive evidence to the effect that our members have killed them,”  he says.)

Other Abahlali baseMjondolo activists have been killed by what Zikode calls “izinkabi,” hitmen hired by politicians. Two eThekwini city councillors were sentenced to life in prison 2016 after they organized the killing of Thuli Ndlovu, an Abahlali baseMjondolo organizer. A member of the Land Invasion Unit who is currently facing a charge of attempted murder after severely injuring a person during an eviction remains on the job, Zikode says.

South Africa’s 1996 constitution is intended to protect the public from arbitrary state violence and guarantees a right to housing, as well as due process in evictions. But for Zikode, the South African constitution is a “beautiful document on a shelf”.

“For the working class and the poor, it’s still difficult to have access to court. You’ve got to have money to get to court,” he says. 

The actions by municipal law enforcement are breaking down social trust, says Buhle Booi, a member of the Khayelitsha Community Action Network, a community group in the largest township in Cape Town.

“There’s a lack of police resources and those very few police resources that they have, they use to destroy people’s homes, to destroy people’s peace, rather than fighting crime, real criminal elements that we see in our society,” Booi says.

For him, it’s a continuation of the practices of the colonial and apartheid governments, pushing poor people, most of whom are Black, to the periphery of cities.

Around one-fifth of South Africa’s urban population live in shacks or informal dwellings, according to a 2018 report by SERI. Many more live in substandard housing. City governments maintain that the shacks destroyed during anti-land invasion operations are unfinished and unoccupied. But Edward Molopi, a research and advocacy officer at SERI, says that this claim is an attempt to escape their legal obligations to get a court order and to find alternative accommodation for affected people. 

The roots of the current eviction crisis go back to apartheid, which barred non-white people from living in cities. Between the 1940s and 1970s, tens of thousands of people were forcibly relocated from neighbourhoods like Johannesburg’s Sophiatown and Cape Town’s District Six to remote townships.

In the 26 years following the end of apartheid, deepening economic inequality and rampant unemployment have limited access to formal housing for millions of South Africans. Government housing programs have mostly focused on building small stand-alone homes, often on the peripheries of cities far from jobs and amenities.

While these well-intentioned projects have built millions of homes, they’ve failed to keep up with demand, says Marie Huchzermeyer, a professor at the Centre for Urbanism & Built Environment Studies at the University of the Witwatersrand in Johannesburg. Government-funded housing projects “will never on it’s own be enough,” she says. “It has to be accompanied by land release.”

Government policies call for the “upgrading” of informal settlements and the formalization of residents’ occupation. But “there are still very, very, very few projects” of that nature in South Africa, Huchzermeyer says. “Even if it’s an informal settlement that’s been around for 20 years, there still seems to be a political wish to punish people for having done that.” The government wants people to go through the formal process of being given a house, she says – and for them to be thankful to the government for providing it.

At the municipal level, change will require “real leadership around informal settlement upgrading and around ensuring that land is available for people to occupy,” she says. 

Despite the end of enforced racial segregation, spacial apartheid remains a factor in South Africa. There are few mixed-income neighbourhoods. Those who can afford to often live behind walls in sprawling low-density suburbs, while the poor live in overcrowded slums and apartment buildings.

The creation of the apartheid city “didn't happen by chance,” says Amira Osman, a professor of architecture at the Tshwane University of Technology. “It was a deliberate, structured approach to the design of the city. We need a deliberate, structured approach that will undo that.”

Since last fall, Johannesburg’s Inclusionary Housing Policy has required developments of 20 or more units to set aside 30% of those units for low-income housing.

The policy, which faced significant opposition from private developers, won’t lead to dramatic change, says Sarah Charlton, a professor at the Centre for Urbanism and Built Environment Studies, but it is “an important and significant step.”

Zikode isn’t optimistic that change will come for shack dwellers, however.

“People in the high positions of authority pretend that everything is normal,” he says. “They pretend that everyone is treated justly, they pretend that everyone has homes with running water, that everyone has a piece of land – and hide the truth and the lies of our democracy.”

Jacob Serebrin is a freelance journalist currently based in Johannesburg. Follow him on Twitter.