Urban Emissions Modeling using the Metropolis Multi-Agent Framework: The Case of Riyadh City

Urban mobility-related emissions are a growing concern in rapidly expanding cities, driving the need for robust methods to assess and mitigate their environmental impact. Here, we focus on developing a multi-agent model to estimate emissions in Riyadh city as the primary case study. Specifically, this study employs the dynamic traffic simulator, METROPOLIS2, to examine mobility-related emissions and their environmental impact. The framework integrates a cleaned road network, an origin–destination matrix for 162 zones with node– zone assignment, and a simplified metro layer. The model is calibrated to reproduce observed congestion patterns and verified through day-to-day dynamics—convergence in departure/arrival times, route reallocation under congestion, and distance–emissions comovement under a homogeneous fleet. We report generalized cost and emissions indicators at the trip and network levels. The contribution is methodological: a transparent, reproducible baseline for Riyadh that enables credible scenario evaluation.