Birmingham is considering a 20mph speed limit in the southern half of the city. Will it work?

Those were the days: a traffic policeman in Birmingham in 1926. Image: Hulton Archive/Getty.

Birmingham City Council, the largest local authority in Europe, has announced proposals to implement 20 miles per hour speed limits on roads across much of the southern half of the city. It has already enforced reductions from the 30mph limit on roads near schools; but now there’s growing support for a wider rollout.

Emergency vehicles like ambulances will be exempt – but the hope this that wider 20mph limits will persuade drivers of other vehicles to better share the road with each other, pedestrians, and cyclists. The rationale behind this in Birmingham applies to any other city in the country: the authorities want to reduce the severity and number of accidents. They aim to lower air and noise pollution, too.

Previous consultations showed stronger support from those who walk, cycle, and use public transport – so convincing those who primarily drive will be the key challenge. There is also widespread support amongst other key stakeholders: businesses, schools, the police, environmental groups, and transport and delivery groups.

Evidence from several towns and cities across England shows that the implementation of 20mph limits reduces the number and severity of road traffic collisions. A pedestrian, if struck by a vehicle driving at 20mph, is likely to suffer slight injuries. At 30mph they will probably be severely hurt; at 40mph or above, they are likely to be killed.

There are, of course, still concerns about the potential negative impacts of a 20mph speed limit – the most frequent being that it would increase congestion.


But that might not actually be true. While travelling at 20mph would obviously take longer than travelling at 30mph on a clear stretch of road, research shows that vehicles flow more smoothly through junctions at slower speeds. This would have a much greater impact in an urban environment, particularly in cities with older road networks.

Some may doubt that 20mph limits can reduce noise and air pollution. A study conducted in Graz, Austria, found that an introduction of 18mph limits back in 1992 led to a noise reduction up to 2.5 dB. Compared to 30mph, 20mph would mean three decibels less traffic noise. There is no conclusive study yet regarding the impact on the environment, but, as a result of reduced acceleration and braking, a 20mph limit may help to reduce fuel consumption and associated emissions.

 Ultimately, the driving issue – forgive the pun – is what impact all this will have on journey times. Plans in Birmingham, much like those elsewhere, still retain some roads at the 30mph or 40mph limit. This should mean most journeys wouldn’t be significantly affected; and, in the case of those urban roads littered with junctions, the improved traffic flow could actually reduce overall journey times.

Still, reducing speed limits will inevitably prompt some motorists to feel penalised. Many will assume it will be a hindrance, even if the evidence says journeys will take the same time at most, be much safer and pleasant for themselves and others, and consume less fuel. The only way to convince critics is by testing 20mph out first and then judging the results.

Luckily, we already have a few case studies to go on.

In the Sherwood area of Nottingham, which has had a full year of 20mph on residential roads, average speeds have gone down by 5.2 per cent. At the same time, casualties in road traffic collisions have decreased from an average of 9.4 per year before implementation, to 8.0 in the year following implementation; most of these were deemed “slight”, rather than severe. In Portsmouth, 20mph limits lowered casualties in road traffic collisions by a further 8 per cent than may have otherwise occurred. In Warrington, collisions in the 20mph speed limit areas fell by a whole 25 per cent; Bristol, Edinburgh, and Dublin have all seen similar results.

Across Europe and the United States, a number of cities have proposed or adopted 20mph or 30 km per hour (about 19mph) limits. New York City has led the way, implementing numerous neighbourhood-scale 20mph zones. Ten other US states also allow for 15 or 20mph limits, mostly in school zones and business districts. They are ubiquitous in the Netherlands, cover 80 per cent of Munich, and a network of 67 European NGOs have pressed the European Union to make 30kmph the normal limit, with 50kmph the exception.

Birmingham is the former centre of Britain’s motor manufacturing industry, something which explains why so much of the city is so geared (sorry) towards cars. As CityMetric editor Jonn Elledge has written in these pages before:

“Outside [the city centre] you quickly run into a world of six-lane highways and traffic jams that snarl up every rush hour because, in large chunks of the city, the only way to get to work is by road.”

So in some ways it seems strange that moves to improve travelling by road have taken so much longer to be proposed here than in other cities where public transport makes them less dependent on roads for daily commutes.

Safer roads, cleaner air, savings on fuel, and less traffic noise would all be welcome changes – and not just in Birmingham. It is one of 16 UK cities the European Commission has issued warnings to our government over due to lethal levels of pollution.

But for the new speed limits are really to affect change, they’ll be dependent on two things. One is motorists obeying the new law; the other is the authorities enforcing it. Time will tell.

 
 
 
 

What does the Greater Manchester Spatial Plan mean for the region’s housing supply and green belt?

Manchester. Image: Getty.

We’re not even halfway through January and we’ve already seen one of the biggest urban stories of the year – the release of Greater Manchester’s new spatial plan for the city-region. The Greater Manchester Spatial Framework (GMSF) sets an ambitious target to build more than 200,000 homes over the next 18 years.

Despite previous statements indicating greenbelt development was off the table, the plan allows for some moderate easing of greenbelt, combined with denser city centre development. This is sensible, pragmatic and to be welcomed but a question remains: will it be enough to keep Manchester affordable over the long-term?

First, some history on Manchester’s housing strategy: This is not the first iteration of the controversial GMSF. The first draft was released by Greater Manchester’s council leaders back in October 2016 (before Andy Burnham was in post), and aimed to build 227,000 houses by 2037. Originally, it proposed releasing 8.2 per cent of the green belt to provide land for housing. Many campaigners opposed this, and the newly elected mayor, Andy Burnham, sent the plan back to the drawing board in 2017.

The latest draft published this week contains two important changes. First, it releases slightly less greenbelt land than the original plan, 4.1 per cent of the total, but more than Andy Burnham previously indicated he would. Second, while the latest document is still ambitious, it plans for 26,000 fewer homes over the same period than the original.

To build up or to build out?

In many cities, the housing supply challenge is often painted as a battle-ground between building high-density homes in the city centre or encroaching on the green belt. Greater Manchester is fortunate in that it lacks the density of cities such as London – suggesting less of a confrontation between people who what to build up and people who want to build out.

Prioritising building on Greater Manchester’s plentiful high-density city centre brownfield land first is right and will further incentivise investment in public transport to reduce the dependence of the city on cars. It makes the goal in the mayor’s new transport plan of 50 per cent of all journeys in Greater Manchester be made on foot, bikes or public transport by 2040 easier to realise.

However, unlike Greater London’s greenbelt which surrounds the capital, Greater Manchester’s green belt extends deep into the city-region, making development on large amounts of land between already urbanised parts of the city-region more difficult. This limits the options to build more housing in parts of Greater Manchester close to the city centre and transport nodes. The worry is that without medium-term reform to the shape of Manchester’s green belt, it may tighten housing supply in Manchester even more than the green belt already does in places such as London and York. In the future, when looking to undertake moderate development on greenbelt land, the mayor should look to develop in these areas of ‘interior greenbelt’ first.

Greater Manchester’s Green Belt and Local Authority Boundaries, 2019.

Despite the scale of its ambition, the GMSF cannot avoid the sheer size of the green belt forever: it covers 47 per cent of the total metropolitan area). In all likelihood, plans to reduce the size of the green belt by 2 per cent will need to be looked at again once the existing supply of brownfield land runs low – particularly if housing demand over the next 18 years is higher than the GMSF expects, which should be the case if the city region’s economy continues to grow.

An example of a successful political collaboration

The GMSF was a politically pragmatic compromise achieved through the cooperation of the metropolitan councils and the mayoral authority to boost the supply of homes. It happened because Greater Manchester’s mayor has an elected mandate to implement and integrate the GMSF and the new transport plan.

Other cities and the government should learn from this. The other metro mayors currently lacking spatial planning powers, in Tees Valley and the West Midlands, should be gifted Greater Manchester-style planning powers by the government so they too can plan and deliver the housing and transport their city-regions need.

Long-term housing strategies that are both sustainable and achievable need to build both up and out. In the short-term Greater Manchester has achieved this, but in the future, if its economic success is maintained, it will need to be bolder on the green belt than the proposals in the current plan. By 2037 Manchester will not face a trade-off between high-density flats in the city centre or green belt reform – it will need to do both.  If the city region is to avoid the housing problems that bedevil London and other successful cities, policy makers need to be ready for this.

Anthony Breach is an economic analyst at the Centre for Cities, on whose blog this post first appeared.