A Smart city is an urban area that uses different types of electronic Internet of Things (IoT) sensors to collect data and then use these data to manage assets and resources efficiently. This includes data collected from citizens, devices, and assets that is processed and analyzed to monitor and manage traffic and transportation systems, power plants, water supply networks, waste management, crime detection,^[1] information systems, schools, libraries, hospitals, and other community services.^[2][3]

The Smart city concept integrates information and communication technology (ICT), and various physical devices connected to the IoT network to optimize the efficiency of city operations and services and connect to citizens.^[4][5] Smart city technology allows city officials to interact directly with both community and city infrastructure and to monitor what is happening in the city and how the city is evolving. ICT is used to enhance quality, performance and interactivity of urban services, to reduce costs and resource consumption and to increase contact between citizens and government.^[6] Smart city applications are developed to manage urban flows and allow for real-time responses.^[7] A Smart city may therefore be more prepared to respond to challenges than one with a simple "transactional" relationship with its citizens.^[8][9] Yet, the term itself remains unclear to its specifics and therefore, open to many interpretations.^[10]

Major technological, economic and environmental changes have generated interest in smart cities, including climate change, economic restructuring, the move to online retail and entertainment, ageing populations, urban population growth and pressures on public finances.^[11] The European Union (EU) has devoted constant efforts to devising a strategy for achieving 'smart' urban growth for its metropolitan city-regions.^[12][13] The EU has developed a range of programmes under 'Europe's Digital Agenda".^[14] In 2010, it highlighted its focus on strengthening innovation and investment in ICT services for the purpose of improving public services and quality of life.^[13] Arup estimates that the global market for smart urban services will be $400 billion per annum by 2020.^[15] Examples of Smart city technologies and programs have been implemented in Singapore,^[16] Dubai,^[17] Milton Keynes,^[18] Southampton,^[19] Amsterdam,^[20] Barcelona,^[21] Madrid,^[22] Stockholm,^[23] Copenhagen ^[163] , China^[24] and New York.^[25]

Due to the breadth of technologies that have been implemented under the Smart city label, it is difficult to distill a precise definition of a Smart city. Deakin and Al Wear^[26] list four factors that contribute to the definition of a Smart city:

Deakin defines the Smart city as one that utilises ICT to meet the demands of the market (the citizens of the city), and that community involvement in the process is necessary for a Smart city.^[27] A Smart city would thus be a city that not only possesses ICT technology in particular areas, but has also implemented this technology in a manner that positively impacts the local community.

Alternative definitions include:

It has been suggested that a Smart city (also community, business cluster, urban agglomeration or region) uses information technologies to:

They evolve towards a strong integration of all dimensions of human intelligence, collective intelligence, and also artificial intelligence within the city.^[41][42] The intelligence of cities "resides in the increasingly effective combination of digital telecommunication networks (the nerves), ubiquitously embedded intelligence (the brains), sensors and tags (the sensory organs), and software (the knowledge and cognitive competence)".^[43]

These forms of intelligence in smart cities have been demonstrated in three ways:

Some major fields of intelligent city activation are:

According to David K. Owens, the former executive vice president of the Edison Electric Institute, two key elements that a Smart city must have are an integrated communications platform and a "dynamic resilient grid." Both are large investments.^[46]

The creation, integration, and adoption of Smart city capabilities requires a unique set of frameworks to realize the focus areas of opportunity and innovation central to Smart city projects. The frameworks can be divided into 5 main dimensions which include numerous related categories of Smart city development:^[47]

A Smart city relies heavily on the deployment of technology. Different combinations of technological infrastructure interact to form the array of Smart city technologies with varying levels of interaction between human and technological systems.^[48]

Smart city initiatives have measurable positive impacts on the quality of life of its citizens and visitors.^[56] The human framework of a Smart city - its economy, knowledge networks, and human support systems - is an important indicator of its success.^[57]

According to Moser, M. A.,^[62] since the 1990s, the Smart Communities movement took shape as a strategy to broaden the base of users involved in IT. Members of these Communities are people that share their interest and work in a partnership with government and other institutional organizations to push the use of IT to improve the quality of daily life as a consequence of different worsening in daily actions. Eger, J. M.^[65] said that a smart community makes a conscious and agreed-upon decision to deploy technology as a catalyst to solving its social and business needs. It is very important to understand that this use of IT and the consequent improvement could be more demanding without the institutional help; indeed institutional involvement is essential to the success of smart community initiatives. Again Moser, M. A.^[62] explained that "building and planning a smart community seeks for smart growth"; smart growth is essential for the partnership between citizen and institutional organizations to react to worsening trends in daily issues like traffic congestion, school overcrowding and air pollution. However, it is important to note that technological propagation is not an end in itself, but only a means to reinventing cities for a new economy and society. To sum up, it is possible to assert that any Smart city initiatives necessitate the government's support for their success.

The importance of these three different dimensions is that only a link among them can make possible the development of a real Smart city concept. According to the definition of Smart city given by Caragliu, A., Del Bo, C., & Nijkamp, P.,^[66] a city is smart when investments in human/social capital and IT infrastructure fuel sustainable growth and enhance quality of life, through participatory governance.

Smart cities use data and technology to create efficiencies, improve sustainability, create economic development, and enhance quality of life factors for people living and working in the city. It also means that the city has a smarter energy infrastructure. More formally, a Smart city is: "… An urban area that has securely integrated technology across the information . . . and Internet of Things (IoT) sectors to better manage a city’s assets."^[67]

A Smart city is powered by "smart connections" for various items such as street lighting, smart buildings, distributed energy resources (DER), data analytics, and smart transportation. Amongst these things, energy is paramount; this is why utility companies play a key role in smart cities. Electric companies, working partnership with city officials, technology companies and a number of other institutions, are among the major players that helped accelerate the growth of America's smart cities.^[68]

Smart cities employ a combination of data collection, processing, and disseminating technologies in conjunction with networking and computing technologies and data security and privacy measures encouraging the application of innovation to promote the overall quality of life for its citizens and covering dimensions that include: utilities, health, transportation, entertainment and government services.^[69]

New Internet technologies is platform for promoting cloud-based services, the Internet of Things (IoT),^[70] real-world user interfaces, use of smart phones^[71] and smart meters, networks of sensors and RFIDs, and more accurate communication based on the semantic web, open new ways to collective action and collaborative problem solving.

Online collaborative sensor data management platforms are on-line database services that allow sensor owners to register and connect their devices to feed data into an on-line database for storage and allow developers to connect to the database and build their own applications based on that data.^[72][73]

In London, a traffic management system known as SCOOT optimises green light time at traffic intersections by feeding back magnetometer and inductive loop data to a supercomputer, which can co-ordinate traffic lights across the city to improve traffic throughout.^[74]

The city of Santander in Cantabria, northern Spain, has 20,000 sensors connecting buildings, infrastructure, transport, networks and utilities, offers a physical space for experimentation and validation of the IoT functions, such as interaction and management protocols, device technologies, and support services such as discovery, identity management and security^[75] In Santander, the sensors monitor the levels of pollution, noise, traffic and parking.

Electronic cards (known as smart cards) are another common platform in Smart city contexts. These cards possess a unique encrypted identifier that allows the owner to log into a range of government provided services (or e-services) without setting up multiple accounts. The single identifier allows governments to aggregate data about citizens and their preferences to improve the provision of services and to determine common interests of groups. This technology has been implemented in Southampton.^[26]

Retractable bollards allow to restrict access inside city centers (i.e. to delivery trucks resupplying outlet stores, ...). Opening and closing of such barriers is traditionally done manually, through an electronic pass^[76] but can even be done by means of ANPR camera's connected to the bollard system.^[77][78]

Kyiv has a transport dispatch system. It contains GPS trackers, installed on public transportation, as well as 6,000 video surveillance cameras which monitor the traffic. The accrued data is used by local Traffic Management Service and transport application developers.

A Smart city roadmap consists of four/three (the first is a preliminary check) major components:^[3][79]

In short, People, Processes, and Technology (PPT) are the three principles of the success of a Smart city initiative. Cities must study their citizens and communities, know the processes, business drivers, create policies, and objectives to meet the citizens' needs. Then, technology can be implemented to meet the citizens' need, in order to improve the quality of life and create real economic opportunities.This requires a holistic customized approach that accounts for city cultures, long-term city planning, and local regulations.

University research labs developed prototypes for intelligent cities. IGLUS is an action research project led by EPFL focused on developing governance systems for urban infrastructures. IGLUS announced a MOOC through Coursera.^[81] MIT Smart Cities Lab^[82] focuses upon intelligent, sustainable buildings, mobility systems (GreenWheel electric bicycle, mobility on demand, CityCar, Wheel Robots); the IntelCities^[83] research consortium for electronic government, planning systems and citizen participation; URENIO developed intelligent city platforms for the innovation economy^[84] focusing on strategic intelligence, technology transfer, collaborative innovation, and incubation, while it promotes intelligent cities research and planning;^[85] the Smart Cities Academic Network^[86] is working on e-governance and e-services in the North Sea region. The MK:Smart project^[18] is focusing on issues of sustainable energy use, water use and transport infrastructure alongside exploring how to promote citizen engagement^[87] alongside educating citizens about smart cities.^[88][89] Research journals in this area include the UK IET Smart Cities, which was launched in 2018.^[90]

Large IT, telecommunication and energy management companies such as Huawei, Alibaba, Tencent, Baidu, Cisco, Google, Schneider Electric, IBM and Microsoft market initiatives for intelligent cities. Cisco, launched the Global Intelligent Urbanization initiative^[91] to help cities using the network as the fourth utility for integrated city management, better quality of life for citizens, and economic development. IBM announced its SmarterCities^[92] to stimulate economic growth and quality of life in cities and metropolitan areas with the activation of new approaches of thinking and acting in the urban ecosystem. Sensor developers and startup companies are continually developing new Smart city applications.

Major strategies and achievements related to the spatial intelligence of cities are listed in the Intelligent Community Forum awards from 1999 to 2010, in the cities of Songdo and Suwon (South Korea), Stockholm (Sweden), Gangnam District of Seoul (South Korea), Waterloo, Ontario (Canada), Taipei (Republic of China), Mitaka (Japan), Glasgow (Scotland, UK), Calgary (Alberta, Canada), Seoul (South Korea), New York City (US), LaGrange, Georgia (US), and Singapore, which were recognized for their efforts in developing broadband networks and e-services sustaining innovation ecosystems, growth, and inclusion.^[93] There are a number of cities actively pursuing a Smart city strategy:

The Amsterdam Smart city initiative^[20] which began in 2009 currently includes 170+ projects collaboratively developed by local residents, government and businesses.^[27] These projects run on an interconnected platform through wireless devices to enhance the city's real-time decision making abilities. The City of Amsterdam (City) claims the purpose of the projects is to reduce traffic, save energy and improve public safety.^[95] To promote efforts from local residents, the City runs the Amsterdam Smart city Challenge annually, accepting proposals for applications and developments that fit within the City's framework.^[96] An example of a resident developed app is Mobypark, which allows owners of parking spaces to rent them out to people for a fee.^[97] The data generated from this app can then be used by the City to determine parking demand and traffic flows in Amsterdam. A number of homes have also been provided with smart energy meters, with incentives provided to those that actively reduce energy consumption.^[7][98] Other initiatives include flexible street lighting (smart lighting)^[99] which allows municipalities to control the brightness of street lights, and smart traffic management^[100] where traffic is monitored in real time by the City and information about current travel time on certain roads is broadcast to allow motorists to determine the best routes to take.

″Lahore Smart city″ in Pakistan initiative has been established to create favorable conditions for further development and increased public safety in city management. Such an approach lays the fundamental principles of infrastructural, technological and social development of Lahore, and defines the future transformation of the city area. The Project had ARUP as project consultant . Huawei as project contractor and currently Urbane Private Limited ^[165] as operations and maintenance company. The project is governed by a Pakistani government body Punjab safe cities authority .

Barcelona has established a number of projects that can be considered 'Smart city' applications within its "CityOS" strategy.^[101] For example, sensor technology has been implemented in the irrigation system in Parc del Centre de Poblenou, where real time data is transmitted to gardening crews about the level of water required for the plants.^[21][102] Barcelona has also designed a new bus network based on data analysis of the most common traffic flows in Barcelona, utilising primarily vertical, horizontal and diagonal routes with a number of interchanges.^[103] Integration of multiple Smart city technologies can be seen through the implementation of smart traffic lights^[104] as buses run on routes designed to optimise the number of green lights. In addition, where an emergency is reported in Barcelona, the approximate route of the emergency vehicle is entered into the traffic light system, setting all the lights to green as the vehicle approaches through a mix of GPS and traffic management software, allowing emergency services to reach the incident without delay. Much of this data is managed by the Sentilo Platform.^[105][106]

In the summer of 2017, the City of Columbus, Ohio began its pursuit of a Smart city initiative. It partnered with American Electric Power Ohio to create a group of new electric vehicle charging stations. Many smart cities such as Columbus are using agreements such as this one to prepare for climate change, expand electric infrastructure, convert existing public vehicle fleets to electric cars, and create incentives for people to share rides when commuting. For doing this, the U.S. Department of Transportation gave the City of Columbus a $40 million grant. The city also received $10 million from Vulcan Inc.^[107]

One key reason why the utility was involved in the picking of locations for new electric vehicle charging stations was to gather data. According to Daily Energy Insider, the group Infrastructure and Business Continuity for AEP said, "You don't want to put infrastructure where it won't be used or maintained. The data we collect will help us build a much bigger market in the future."^[107]

Because autonomous vehicles are currently seeing "an increased industrial research and legislative push globally", building routes and connections for them is another important part of the Columbus Smart city initiative.^[107]

In 2014, Copenhagen claimed the prestigious World Smart Cities Award for its “Connecting Copenhagen” Smart city development strategy.^[108] Positioned in the Technical and Environmental Administration of Copenhagen, the Smart city initiatives are coordinated by Copenhagen Solutions Lab ^[166] , the city’s administrative unit for Smart city development. There are other notable actors in Greater Copenhagen that coordinate and initiate Smart city initiatives including State of Green ^[167] and Gate21 ^[168] , the latter of which has initiated the innovation hub Smart city Cluster Denmark ^[169] .

In an article with The Economist^[109], a current major Smart city project is explained: “In Copenhagen, as in many cities around the world, air quality is high on the agenda when it comes to liveability, with 68 percent of citizens citing it as of high importance when it comes to what makes their city attractive. To monitor pollution levels, Copenhagen Solutions Lab is currently working with Google and has installed monitoring equipment in their streetview car in order to produce a heatmap of air quality around the city. The information will help cyclists and joggers plan routes with the best air quality. The project also gives a glimpse of the future, when this kind of information could be collected in real time by sensors all over the city and collated with traffic flow data.”

In another article with The World Economic Forum, Marius Sylvestersen, Program Director at Copenhagen Solutions Lab, explains that public-private collaborations must be built on transparency, the willingness to share data and must be driven by the same set of values. This requires a particularly open mindset from the organisations that wish to get involved. To facilitate open collaboration and knowledge-sharing, Copenhagen Solutions Lab launched the Copenhagen Street Lab in 2016. Here, organisations such as TDC, Citelum and Cisco work in collaboration with Copenhagen Solutions Lab to identify new solutions to city and citizen problems.

In 2013, the Smart Dubai project was initiated by Shaikh Mohammad bin Rashid Al Maktoum, vice president of UAE, which contained more than 100 initiatives to make Dubai a Smart city by 2030. The project aimed to integrate private and public sectors, enabling citizens to access these sectors through their smartphones. Some initiatives include the Dubai Autonomous Transportation Strategy to create driverless transits, fully digitizing government, business and customer information and transactions, and providing citizens 5000 hotspots to access government applications by 2021.^[110][111] Two mobile applications, mPay and DubaiNow, facilitate various payment services for citizens ranging from utilities or traffic fines to educational, health, transport, and business services. In addition, the Smart Nol Card is a unified rechargeable card enabling citizens to pay for all transportation services such as metro, buses, water bus, and taxis. There is also the Dubai Municipality's Digital City initiative which assigns each building a unique QR code that citizens can scan containing information about the building, plot, and location.^[112]

Dublin finds itself as an unexpected capital for smart cities.^[113] The Smart city programme for the city is run by Smart Dublin^[114] an initiative of the four Dublin Local Authorities to engage with smart technology providers, researchers and citizens to solve city challenges and improve city life. It includes Dublinked- Dublin's open data platform that hosts open source data to Smart city applications.

Madrid, Spain's pioneering Smart city,^[115] has adopted the MiNT Madrid Inteligente/Smarter Madrid platform to integrate the management of local services. These include the sustainable and computerized management of infrastructure, garbage collection and recycling, and public spaces and green areas, among others.^[116] The programme is run in partnership with IBMs INSA, making use of the latter's Big Data and analytics capabilities and experience.^[117] Madrid is considered to have taken a bottom-up approach to smart cities, whereby social issues are first identified and individual technologies or networks are then identified to address these issues.^[118] This approach includes support and recognition for start ups through the Madrid Digital Start Up programme.^[119]

A document written in 2011 refers to 18th century Żejtun as the earliest "Smart city" in Malta,^[120] but not in the modern context of a Smart city. By the 21st century, SmartCity Malta, a planned technology park, became partially operational while the rest is under construction, as a Foreign Direct Investment.

In December 2015, Manchester's CityVerve project was chosen as the winner of a government-led technology competition and awarded £10m to develop an Internet of Things (IoT) smart cities demonstrator.^[121]

Established in July 2016, the project is being carried out by a consortium of 22 public and private organisations, including Manchester City Council, and is aligned with the city's on-going devolution commitment.^[122]

The project has a two-year remit to demonstrate the capability of IoT applications and address barriers to deploying smart cities, such as city governance, network security, user trust and adoption, interoperability, scalability and justifying investment.

CityVerve is based on an open data principle that incorporates a "platform of platforms"^[123] which ties together applications for its four key themes: transport and travel; health and social care; energy and the environment; culture and the public realm. This will also ensure that the project is scalable and able to be redeployed to other locations worldwide.

Milan, Italy was prompted to begin its Smart city strategies and initiatives by the European Union's Smart Cities and Communities initiative. However, unlike many European cities, Milan's Smart city strategies focus more on social sustainability rather than environmental sustainability.^[124] This focus is almost exclusive to Milan and has a major influence in the way content and way its strategies are implemented as shown in the case study of the Bicocca District in Milan.^[125]

Milton Keynes has a commitment to making itself a Smart city. Currently the mechanism through which this is approached is the MK:Smart initiative,^[18] a collaboration of local government, businesses, academia and 3rd sector organisations. The focus of the initiative is on making energy use, water use and transport more sustainable whilst promoting economic growth in the city. Central to the project is the creation of a state-of-the-art 'MK Data Hub' which will support the acquisition and management of vast amounts of data relevant to city systems from a variety of data sources. These will include data about energy and water consumption, transport data, data acquired through satellite technology, social and economic datasets, and crowdsourced data from social media or specialised apps.

The MK:Smart initiative has two aspects which extend our understanding of how Smart Cities should operate. The first, Our MK,^[87] is a scheme for promoting citizen-led sustainability issues in the city. The scheme provides funding and support to engage with citizens and help turn their ideas around sustainability into a reality. The second aspect is in providing citizens with the skills to operate effectively in a Smart city. The Urban Data school^[88] is an online platform to teach school students about data skills while the project has also produced a MOOC^[89] to inform citizens about what a Smart city is.

^[126][127]

New York City is developing a number of Smart city initiatives. A notable example is the series of city service kiosks in the LinkNYC network. These provide services including free WiFi, phone calls, device charging stations, local wayfinding, and more, funded by advertising that plays on the kiosk's screens.

The city of San Leandro, California is in the midst of transforming from an industrial center to a tech hub of the Internet of things (IoT) (technology that lets devices communicate with each other over the Internet). California's utility company PG&E is working with the city in this endeavor and on a smart energy pilot program that would develop a distributed energy network across the city that would be monitored by IoT sensors. The goal would be to give the city an energy system that has enough capacity to receive and redistribute electricity to and from multiple energy sources.^[67]

An alternative use of Smart city technology can be found in Santa Cruz, California, where local authorities analyse historical crime data in order to predict police requirements and maximise police presence where it is required.^[128] The analytical tools generate a list of 10 places each day where property crimes are more likely to occur, and then placing police efforts on these regions when officers are not responding to any emergency. This use of ICT technology is different to the manner in which European cities utilise Smart city technology, possibly highlighting the breadth of the Smart city concept in different parts of the world.

Shanghai's development of the IoT and internet connection speeds have allowed for third party companies to revolutionize the productivity of the city.^[129] As mobile ride share giant, DiDi Chuxing, continuously adds more user protection features such as ride recording, and a new quick response safety center, Shanghai is furthering their Smart city agenda.^[130] During the first China International Import Expo, Shanghai focused on smart mobility and implemented sensors to accept smartphone traffic cards in all metro stations and buses to increase efficiency in the city.

The Smart Cities Mission is a retrofitting and urban renewal program being spearheaded by the Ministry of Urban Development, Government of India. The Government of India has the ambitious vision of developing 100 cities by modernizing existing mid-sized cities.^[131]

Despite its size and lack of natural resources, Singapore (a city-state) has overcome many of its challenges in 50 short years to become one of the world's most advanced and livable countries. It has embarked on its next phase of transformation towards a Smart Nation, and endeavours to harness the power of networks, data and info-comm technologies to improve living, create economic opportunities and build closer communities.

Stockholm's Smart city technology is underpinned by the Stokab dark fibre system^[132] which was developed in 1994 to provide a universal fibre optic network across Stockholm.^[133] Private companies are able to lease fibre as service providers on equal terms. The company is owned by the City of Stockholm itself.^[23] Within this framework, Stockholm has created a Green IT strategy.^[134] The Green IT program seeks to reduce the environmental impact of Stockholm through IT functions such as energy efficient buildings (minimising heating costs), traffic monitoring (minimising the time spent on the road) and development of e-services (minimising paper usage). The e-Stockholm platform is centred on the provision of e-services, including political announcements, parking space booking and snow clearance.^[135] This is further being developed through GPS analytics, allowing residents to plan their route through the city.^[135] An example of district-specific Smart city technology can be found in the Kista Science City region.^[136] This region is based on the triple helix concept of smart cities,^[36] where university, industry and government work together to develop ICT applications for implementation in a Smart city strategy.

Taipei start Smarttaipei project since 3/20/2016, the major concept of Smarttaipei is to change the culture^[137] of city hall government to be able to adopt new ideas and new concepts call bottom-up mechanism, and the Taipei Smart city Project management office(TPMO) play a key role of this project. TPMO accept proposals from industry and help to negotiate with relative department of Taipei city to initiate new proof of concept(PoC) project, there are more than 150^[138] PoC Project established, and only 34% project finished. Dr. Chen-Yu Lee^[139], director of TPMO, is the major planner/executor of this project.

″Kyiv Smart city″ initiative has been established to create favorable conditions for further development and increased public involvement in city management. Such an approach lays the fundamental principles of infrastructural, technological and social development of Kyiv, and defines the future transformation of the city area. There are several public projects, based on digital technologies, in Kyiv. For example, there is ″Kyiv Resident Card″, which provides access to local innovations and serves as an e-ticket for all types of public transportation. Ultimately, the ″Smart city″ concept implies the possibility of managing municipal services online.

The criticisms of smart cities revolve around:^[36]