Keeping cities safe by booting up digital defences

City governments play a vital role in ensuring public safety. People and their property need to be protected from crime and violence, natural and man-made disasters and – increasingly – cyberattacks.

Yet, over recent years, cities have been scarred by tragedies. We saw a deadly crush during Halloween celebrations in Seoul in October 2022. An earthquake killed 228 people and damaged more than 12,000 buildings in Mexico City in September 2017. Terrorist attacks in Paris during November 2015 left deep scars on the city. In the context of mounting threats, how can we keep our cities safe?

Why do cities feel unsafe?

With higher levels of levels of inequality, increased economic insecurity and limited funds for law enforcement, cities may be more vulnerable to crime. In the US, violent crime in urban areas rose 29% between 2020 and 202, from 19 to 24.5 victims per 1 000 inhabitants, and property crime rate was three time higher than in rural areas with 157 to 58 victimisations per 1,000 inhabitants.

Many cities are also exposed to natural risks. It is estimated that about 1 billion people are vulnerable to disasters often due to poor urban planning and corruption; and 3.3 to 3.6 billion people live in a highly vulnerable situation due to climate change.

Security is also an essential platform for economic development, supporting cities to attract investment and skilled workers. It is therefore no surprise that the global market for “safe city” technologies is expected to grow from USD 21.6 billion in 2019 to USD 35.8 billion in 2024.

Do digital technologies make cities safer?

Digital technologies and data have the potential to reduce crime by 30-40%, with surveillance technology proving particularly effective in improving crime control. Across the UK, evidence suggests that CCTV has helped cut property crime by 34%, vehicle crime 32% and violent crime 15%. London now has more than 800 000 cameras.

However, digital technologies are about more than surveillance cameras. Digital infrastructure has facilitated interagency communication, enhanced the targeting of criminals, accelerated policy responsiveness and enhanced interaction with citizens.

Digital technologies help to monitor the state of infrastructure. In the US, IoT devices (sensors) and artificial intelligence (AI) are helping to get predictive insights into cities’ infrastructure such as bridges. On average about 128 bridges collapse due to hydraulic events (e.g. floods, ice) across the country every year. Sensors are also used to control street lighting to protect citizens while reducing energy costs. In Belgium, the cities of Mechelen and Bonheiden use motion sensor-based streetlights to make the streets safer for cyclists and pedestrians at night and minimise maintenance and operational costs, as well as energy consumption.

Not just the London Eye…

The UK’s most-watched cities via surveillance cameras, 2020

Source: IFSEC Global (2020) Revealed: the UK’s most-watched cities, at:

Technology also enhances preparedness in case of emergency and mitigates risk. For instance, Mexico has developed the Mexican Seismic Alert system (SASMEX). This is an early warning system for earthquakes that warns the population of Mexico City through a sound alert up to 90 seconds before an earthquake occurs, helping save lives and reduce the loss of property.

Digital technologies work with broader measures

To be successful, digital technologies must command the confidence of citizens. To build trust, the city of Aizuwakamatsu in Japan adopted the ‘opt-in’ approach to its city smart city initiatives allowing residents to choose if they want to provide personal information in exchange for digital services. So far around 20% of residents have opted-in to share their data. Others like New York City have developed a IoT data framework for guiding decisions on data collection, use, disclosure, and storage.

Cities must also be well planned and integrated across platforms. In India, digital technology-based projects (e.g. central control centres, optical networks, CCTV, IT-enabled services) were key instruments in responding to the COVID-19 pandemic in cities like Gujarat and Nagpur. But the lack of integration among digital technologies and co-ordination and planning prevented a more effective response.

And they must work alongside broader investments in social infrastructure and services. For example, Medellín, Colombia adopted a series of technology-based solutions to curb crime and violence in 2014. The Integrated Security System has helped share data between different departments (e.g., police, health, risk, mobility, and firefighters); and a surveillance camera system with AI was installed.

While such technologies certainly helped address crime, it is also apparent that crime rates began to drop significantly during the late 1990s and early 2000s when the government adopted social urbanism by prioritising better access to basic public services (education, sanitation, clean water and public transport).

Here the key to tackling crime was about tackling inequalities such as poor living conditions just as much as digital technologies. In Mexico as well, although the use of sensors has been key to save lives during earthquakes, vulnerability often derives from socio-economic and development challenges such as marginalisation, informal construction and poverty.

Homicide rates in Medellín and Colombia

Source: Colombia Reports (2022) Crime and Security in Medellin, at:

In Ireland, Dublin’s suburb of Turristown, plagued by spatial degradation, socio-economic deprivation, and crime since the 1960s, has been going through urban regeneration programmes since 1997.

Research has shown that crime prevention measures such as surveillance cameras and security measures in buildings combined with an increased number of pedestrians, natural surveillance by residents, and improved community spirit have contributed to a feeling of safety and crime reduction.

Towards an integrated approach

So, digital technologies play a key role in improving public safety, but there is much more to do. Digital technologies can complement planning and development policies that ensure safety but must be accompanied by broader measures to build confidence, integrate technologies and support more traditional approaches to crime reduction. And of course, cities will also need to demonstrate the positive impact of digital technologies on public safety and put in place safeguards to build trust and support for their use.

Read more on the OECD work on Cities here.

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Oscar Huerta Melchor is a project manager and policy analyst on public governance and urban development at the OECD Centre for Entrepreneurship, SMEs, Regions and Cities (CFE). Oscar has led and participated in several urban and metropolitan policy reviews and thematic projects on topics such as accessibility, housing, the governance of land use, innovation in cities, smart mobility. Oscar joined OECD in 2007 as a policy analyst on public employment and management at the Public Governance Directorate (GOV). He holds a Masters and a PhD in comparative public policy from the University of York, United Kingdom.