This paper presented a two-vehicle rear-end collision dynamics model for analyzing crash mechanisms in urban traffic and proposed response and control strategies to mitigate secondary congestion and improve post-incident traffic recovery. Rear-end collisions are among the most frequent crash types in urban road networks. They disrupt traffic flow and increase travel delays, fuel consumption as well as emissions, hence triggering secondary crashes if not handled properly. Accurate dynamic modeling of two-vehicle rear-end collisions is essential for improving traffic safety, efficiency of responding to incidents, and design of the vehicle control system. The model mathematically represented the interaction between a leading vehicle and a following vehicle during pre-impact, impact, and post-impact phases. It incorporated conservation of momentum, restitution characteristics, braking dynamics, and vehicle mass properties. The study further examined how response strategies such as rapid clearance, lane management, and adaptive traffic control affected congestion dissipation and traffic recovery. The analysis demonstrated that accurate dynamics modeling enabled reliable estimation of impact severity, post-collision velocities, and clearance time. Optimized response management significantly reduced secondary congestion, shortened traffic recovery time, and enhanced overall roadway performance. The study integrated mechanical collision dynamics with traffic management interventions within a unified analytical framework. Unlike purely traffic-flow-based models, this approach directly linked physical crash mechanics with network-level congestion propagation and response optimization. Future research will extend the model to multi-vehicle chain collisions, incorporate stochastic drivers’ reaction time and braking behavior, and integrate the framework with intelligent transportation systems under dynamic urban traffic conditions.
A sustainable solid waste-based cementitious system was developed using refining slag, steel slag, desulfurized gypsum, and granulated blast furnace slag (GBFS), and its low-temperature hydration behavior was investigated through a combined experimental and modelling approach. The strength development and microstructural evolution of the quaternary system under different curing temperatures were systematically analyzed. A temperature-dependent hydration kinetics interpretation was introduced to explain the variation in mechanical performance. The hydration characteristics were examined using X-ray diffraction (XRD), thermogravimetric–differential scanning calorimetry (TG–DSC), and scanning electron microscopy (SEM). The results indicate that curing temperature plays a dominant role in governing hydration kinetics and strength evolution. The compressive strength shows a clear positive correlation with temperature, which can be attributed to the accelerated formation of hydration products, mainly ettringite (AFt) and calcium silicate hydrate (C–S–H) gel. Under low-temperature conditions, the hydration process is significantly retarded due to reduced ion mobility and suppressed dissolution of solid waste components. The proposed mechanism suggests that refining slag contributes to the activation of the quaternary system by enhancing early-stage hydration reactions and improving structural densification. From a sustainability perspective, the developed system provides an effective pathway for large-scale utilization of industrial solid wastes while reducing dependence on conventional cement. The findings offer both experimental insights and a modelling-oriented interpretation of low-temperature hydration processes, providing a useful reference for the design and optimization of sustainable cementitious systems in cold-region engineering applications.