The development of digital technology has grown at a phenomenal rate during the first quarter of the 21st century. Terrestrial, aerial and satellite sensors provide an ever-increasing range and resolution of real-time attribute and monitoring data. In parallel, data processing software and communication systems have evolved at an equivalent pace. Together, these advances offer the potential for increasingly efficient and effective approaches to the planning, operation and maintenance of infrastructure in towns and cities. However, challenges exist for the owners and managers of infrastructure to take full advantage of this technology and tackle issues related to change management and cyber security.
Digital technology is now so much a part of everyday life that its impact on methods of design, construction and operation in the municipal engineering sector is often taken for granted. Increasingly, digitalisation is changing how municipal authorities deliver services to the public. Evolution towards the creation of smart cities and transportation is facilitated by the development of big datasets, that help define and quantify the full range of parameters and data-driven relationships that inform planning and engineering decision-making. Three-dimensional (3D) representation of urban space is provided by Geographical Information Systems (GIS) integrated with remotely-sensed digital elevation models (DEMs). Cloud computing and mobile technology facilitate effective storage, use and communication of data. However, it is essential to ensure purpose, quality control and scientific objectivity in data collection, processing and analysis, and be aware of the inherent fallibility of all complex systems, however rigorously tested.
This issue of the journal has a particular focus on the use of digital datasets and how they are impacting current practice. The papers range from considerations of how data on pedestrian movement can be used to enhance urban design and public safety to the use of data in real-time to improve the quality of urban and transport infrastructure.
The use of emerging digital technology to monitor and improve the quality of asphalt paving in Scottish road construction is described in the paper by McHale et al. (2023). The temperature of the asphalt mix has a major influence on whether adequate compaction will be achieved. Achieving the correct level of compaction is critical to ensuring material durability and extending pavement life. The study examined how electronic data, collected to monitor delivery vehicles, material temperature and compactor effort, can be used to help reduce safety risks at active construction sites and enhance quality control.
The next two papers consider different aspects of pedestrian behaviour. Zhang and Loo (2023) show how video analytics can be used to quantify pedestrian behaviour and hence gain an understanding of how COVID-19 affected the patterns of movement in a study area of Hong Kong. They examined pedestrian numbers, walking speeds, interaction with public facilities and social mingling using detection and tracking algorithms applied to video footage captured by overhead surveillance cameras. Video pixel co-ordinates were georeferenced using GIS software available in ArcMap and checked using drone photography. The authors note that the technology can be further adjusted and used to identify potential bottlenecks and hot spots of pedestrian crowding before large-scale public events. Digital data is not at the heart of the paper by de Oliveira et al. (2023), but it does make use of on-line collection of questionnaire data defining pedestrian behaviour in relation to potential road traffic accidents (RTAs) in Portugal.
The fourth paper by Barbalho et al. (2023) describes the use of GIS tools to analyse the urban planning problems of a complex mega city, Rio de Janeiro. According to the authors, approximately 20% of the population lives in informal housing (‘slums’), thus aggravating the difficulties associated with accurate and reliable cadastral mapping. Among the issues to be resolved were the representation of sidewalks, the definition of outbuilding structures and the fact that the areal sum of individual land parcels proved not to be the same as the size of the neighbourhoods they comprised. The authors note that in a city known for considerably high crime rates in some neighbourhoods, remotely acquiring positional information is sometimes better than more accurate land surveys. They also conclude that, if correctly characterised and properly defined, current databases may be consolidated into a fully-functioning 3D cadastral representation of the city.
Finally, the paper by Park et al. (2023) describes a study from South Korea to identify the correlation between RTAs and climate change using big data. The RTA dataset included almost 100,000 incidents recorded over a 10-year period on approximately 4,000 km of the highway network. These incidents were examined using correlation and time-series analysis against more than 376,000 weather observations obtained from automated synoptic recording systems in 103 locations across the country. Econometrics and deep-learning models were used to maximise the validity of the analysis. Temperature and precipitation were found to be highly correlated with RTAs, though these outcomes need to be viewed against the background of an overall reduction in RTAs due to advanced driver-assistance, intelligent transport systems, traffic safety, and transportation policies.
GIS has become an indispensable tool for spatial planning in towns and cities. In hilly and mountainous terrain, it is imperative to capture and accommodate the effects of relief on land use planning, and this is usually accomplished using topographic survey or, in recent decades, the digital elevation modelling facilities (DEMs) offered by airborne and satellite remote sensing. However, 3D models of urban areas should also take account of the geology beneath the ground to ensure that planned developments do not become compromised by adverse soil, rock and groundwater conditions. The same applies to above-ground geohazards, such as flooding and landslides, and issues concerning water supply and aquifer protection. Reliable datasets are required to inform municipal authorities and civil engineers, and several case studies have been published for urban areas across the globe. A few examples include those for selected conurbations in the United Kingdom (Culshaw and Price, 2011), Kathmandu, Nepal (Gilder et al., 2020), Thessalonica, Greece (Kokkala and Marinos, 2022) and the Acipayam Municipality in Turkey (Kumsar and Sarayköylü, 2023).
