## 5 DT Technology in the Lifecycle of Transportation Infrastructure
### Construction and Implementation Phase  
For instance, in transport infrastructure construction, such as roads, bridges, and tunnels, problems always occur when prototype design is disconnected from process design, when the components are complicated to manage, and when 2D process documents are unintuitive. DTs integrate physical construction sites with virtual models, offering strong data support and real-time feedback mechanisms [72]. They help in the monitoring of the construction process of transportation infrastructure and continuously update with progress and the consumption of resources. This helps project managers take an effective approach to resource allocation--manpower, machinery, and materials--to ensure that construction work proceeds in accordance with the design plans. This also enables the forecasting of possible problems, timely intervention, and quality control regarding defects and risks that may arise. DT systems can provide services such as construction monitoring and progress management, risk warning and on-site safety management, as well as quality control and compliance inspection during the facility's construction and implementation phase. Sensors can collect data on construction equipment, building materials, and environmental factors like temperature, humidity, and vibration, transmitting that data in real time to the DT platform. Virtual planners and construction managers can virtually see, in real time, what is going on with the construction process. They are able to compare this information against the DT model created during the planning phase, finding variances or warnings regarding potential issues. Feedback from sensor and drone data in the construction of bridges [73] and tunnels [74] enables more effective monitoring of the sections of the construction and ascertains its quality to meet the design standards. In the event of delays or quality issues, the DT system issues warnings in order to aid managers in taking necessary corrective actions and minimizing further delays and quality issues. In addition, the DT can compare historical data with the current status to predict factors that may affect the progress of construction, providing more scientific decision support to managers. It enables project managers to track equipment usage and location in order to optimize equipment utilization and reduce idle time. The DT can also predict possible issues during the construction phase, such as delays in the supply chain or construction errors, thereby allowing preparedness to avoid excessive costs and time consumption [75]. In the construction phase, DT technology manages project progress and provides effective safety risk warnings at construction sites. By analyzing sensor data in real time, it identifies potential risk sources, such as equipment failures, high-risk operation zones, and abnormal environmental conditions. Through intelligent data collection and comprehensive analysis of safety quality, noise, dust, and deformation monitoring, DTs detect and notify stakeholders of safety risks, issue real-time warnings, and support early emergency detection. This technology helps develop an emergency warning system and assesses the impact of emergencies on infrastructure, aiding in the creation and optimization of emergency plans. Ref. [76] developed a multi-information intelligent warning and safety management platform for tunnel construction, characterized by high-risk conditions. A communication network inside the tunnel, established through multifunctional base stations, collects and transmits multisource information. The virtual twin then simulates dynamic construction and surrounding rock conditions, setting up a four-level warning and emergency response system to evaluate the construction status. In projects facing extreme climates, harmful gases, and adverse geology, this system predicted and warned of potential tunnel collapses, facilitating timely emergency actions and ensuring personnel safety.