Fig. 2

(a) Latent class growth mixture model for overall traffic accident mortality trends by province (2006–2022), identifying six distinct classes with unique temporal patterns, such as high initial rates with moderate declines (Class 1: Sistan & Baluchestan, Markazi, Kerman) and sharp reductions from high baselines (Class 2: Semnan). (b) Map of Iranian provinces categorized by latent class, illustrating the geographic distribution of provinces within each class and emphasizing regional disparities in traffic accident mortality trends