In This Issue
Spring Bridge on Sustainable Smart Cities
March 15, 2023
The world’s cities face increasing threats from natural disasters, aging infrastructure, traffic, and resource constraints. The articles in this issue examine smart infrastructure, sustainability, net zero carbon options, and autonomous driving, among other approaches to smart and sustainable cities.

Guest Editor's Note: Engineering for Sustainable Smart Cities

Monday, March 20, 2023

Author: Chai K. Toh

The term smart cities appears in news and media lately but few clearly understand what it means and what it entails. For example, the word smart in this instance does not specifically refer to artificial intelligence. And because sustainability is a rapidly increasing concern around the world, the International Telecommunication Union (ITU) defines a smart sustainable city as “an innovative city that uses information and communication technologies (ICTs) and other means to improve quality of life, efficiency of urban operation and services, and competitiveness, while ensuring that it meets the needs of present and future generations with respect to economic, social, environmental as well as cultural aspects.”[1]

Governments around the world have embarked on smart city projects over the last few years, with investments amounting to millions or billions of dollars, to address concerns such as traffic congestion, air pollution, health hazards, inadequate or outdated infrastructure, and pedestrian safety.

The technologies used to create a smart city include high-speed wireless communications, artificial intelligence (AI), sensors, the Internet of Things, fiber optics, and geospatial engineering, to name just a few. They combine advances in electrical, computer, civil, and environmental engineering, as well as behavioral and geosciences. Thus smart cities require multidisciplinary knowledge, which is rare in the education structure of most universities. There is a need to cultivate more talent with multidisciplinary background; I hope this will be addressed in future research.

Given the growing interest and momentum in smart cities, this issue is timely. The articles describe an “urban metastructure,” strategies for a net zero carbon city, smart infrastructure, a supply-demand framework for resource management, the possibilities of humanoid architectural structure, and vehicle-infrastructure cooperative autonomous driving for smart cities.

In the first article, Anne Kiremidjian[2] and Michael Lepech of Stanford University present an urban metastructure approach to smart and sustainable cities. Using sensing and data collection, computation, and engagement, the metastructure accounts for physical infrastructures, digital technologies, regulations and policies, financing mechanisms, community engagement, businesses and business models, and partnerships to support a high quality of urban life. Acknowledging challenges to the implementation and deployment of smart cities, the authors cite some successful examples.

“Strategies for Net Zero Carbon Cities” by Karen Seto (Yale University’s School of the Environment) reviews high- and low-tech strategies that can be used in combination to achieve a net zero carbon city. In addition to using data, technologies, and systems, cities can reduce energy consumption and carbon emissions by creating bicycle and pedestrian walkways, colocating jobs and housing to reduce commuting traffic, preserving tree canopy, and actively engaging residents in changing their behaviors.

In “Smart Infrastructure for Smart Cities,” Kenichi Soga of UC Berkeley presents the need for intelligent monitoring, learning, anticipating, and responding to infrastructure threats, whether anticipated or unforeseen. He discusses stakeholder roles in the four layers of smart infrastructure: sensors and data collection, data analysis and interpretation, assets, and systems. Digital twins, machine learning, and AI can greatly help in the design, adaptability, monitoring, operation, and longevity of smart infrastructure.

Next, in “IT for Sustainable Smart Cities: A Framework for Resource Management and a Call for Action,” Cullen Bash, Ninad Hogade, and Dejan Milojicic of HP Labs and Chandrakant Patel of HP Inc. discuss the integration of information technologies (IT) in city-scale resource management to achieve sustainability through optimal provisioning. They introduce a holistic urban supply-demand framework, breaking down supply-side resources into city-scale verticals such as power, water, waste management, transport, and health care, and considering design, implementation, and management. To assess lifecycle, their framework uses metrics for “net positive impact” and “net positive carbon impact.” The authors conclude with actions for government, industry, and academia to jointly address sustainable infrastructures in smart cities.

The concepts and components of a “humanoid architectural structure” (HAS) are explained by Xiangsheng Chen, Changqing Xia, Hongzhi Cui, Chengyu Hong, and Min Zhu of Shenzhen University. They explain the use of HAS to realize smart resilient infrastructures through human characteristics such as a robust, flexible, and self-healing “body,” acute “sensory perception,” “intelligence” for self-diagnosis and decision making, and self-protection (“immunity”). An important application of HAS is in underground tunnels, where it can detect and instantly set about “healing” threats such as cracks or raised water levels.

“Smart Infrastructure for Autonomous Driving in Urban Areas,” by Guyue Zhou, Guobin Shang, and Ya-Qin Zhang of Tsinghua University and Baidu, Inc., addresses the current state of vehicle-infrastructure cooperative autonomous driving (VICAD) in China. The authors explain how VICAD can enhance road safety, reduce vehicle collisions, and minimize traffic delays through enhanced perception, coordinated input from sensors and the cloud, data analytics, AI, and collaborative decision making. The article concludes with challenges to be overcome and next steps toward implementation.

This issue considers important aspects of smart cities, from infrastructure to energy to transportation, and provides insights on their role and strategies for achieving net zero carbon emissions and sustainability. I thank the authors for their thoughtful contributions and their willingness to share their knowledge and insights.

Thanks are also due to the experts enlisted to evaluate the submitted drafts: Yilun Chen, Ian T. Foster, Angel Hsu, Hongwei Huang, Robert Mair, Piotr Moncarz, Andrzej Nowak, Thomas D. O’Rourke, Amip Shah, Bill Solecki, B.F. Spencer, Ertugrul Taciroglu, Feng Zhao, and Kun Zhou. Finally, I greatly appreciate the supportive engagement of the Bridge managing editor, Cameron Fletcher.


[1]  Recommendation ITU-T Y.4900

[2]  Bold denotes NAE members.

About the Author:Chai K. Toh (FREng) is Honor Chair Professor of Electrical Engineering and Computer Sciences, National Tsing Hua University.