## 5 Scenarios and Illustrative Applications
### Urban Setting: Montreal, Canada  
Urban environments inherently present a unique set of challenges for outdoor safety monitoring [103]. High population density, complex infrastructure, and dynamic public spaces all contribute to an environment where the potential for accidents increases. Variable microclimates, widespread air pollution, and elevated ambient noise levels complicate the calibration of the sensors and the quality of data [104]. Furthermore, high accuracy requirements require robust, scalable, and fully integrated monitoring systems into the existing urban framework. These complexities must be taken into account when designing IoPVT systems that need to be dynamic and adaptable to the multifaceted nature of urban life, which will help improve both short-term urban safety processes and long-term urban planning initiatives. One of the emerging developments in HAR video surveillance is in outdoor settings near buildings. Outdoor monitoring systems have become quite popular in front of doors to alert for package deliveries, ensure safety surveillance for someone approaching the door, and monitor activity in case of an intrusion. Additionally, an outdoor IoVT system is utilized by convenience stores, pedestrian pathways (especially busy intersections), and public places such as subways to enhance public safety and security. For discussion, another unique scenario for future analysis involves external stairways that can harness existing doorway IoVT developments for urban safety and health monitoring. For instance, Montreal, Canada, has a historical development of external staircases intended to provide safety through community surveillance; however, they can be hazardous in winter conditions, as shown in Figure 4. Ice and snow can make the staircases slippery, creating challenges for elderly individuals who climb the stairs during winter. Therefore, external video surveillance can be employed not only to alert about package deliveries but also as a method to ensure quick responses in case someone slips and falls on the stairs. While this example is a unique case, dense urban centers can benefit from IoVT technology in public spaces with distinctive entrance access. IoPVT systems can install smart sensors along stairs and pedestrian areas to monitor environmental conditions in real time, including temperature drops and ice formation. HAR algorithms can detect abnormal movements, such as slips or hesitations, which can lead to hazardous situations. From a design perspective, precise sensor placement is crucial: devices must be integrated into the cityscape without being unattractive, and their installation must consider factors such as exposure to pollution, potential vandalism, and access to power sources. In addition to IoT considerations, there are network connectivity challenges to face in densely populated urban areas, where sensors must rely on robust, low-latency communication channels that can withstand interference from numerous devices and urban infrastructure. By entering these data into a dynamic digital twin of Montreal's urban environment, emergency services, and municipal maintenance teams can receive timely alerts, allowing them to deploy de-icing or repair crews before accidents happen. Moreover, urban planners can utilize historical aggregated data to pinpoint chronic issues and design lasting interventions, such as more durable stairs or enhanced pedestrian pathways. Additionally, the system should be developed with a robust user interface that offers decision makers visual and analytical insights in real time, along with integration into existing urban management systems and smart city solutions. These features include energy efficiency, modularity, and ease of maintenance, allowing sensors and related infrastructure to be easily scaled or upgraded as technologies advance. This comprehensive approach not only improves public safety in the short term but also promotes the long-term development of the urban landscape in line with Montreal's specific climate and infrastructure needs.