The melting of vector meson peaks in dilepton measurements is a canonical example of medium effects on strongly interacting matter. In the context of on-shell hadronic transport, where the resonance has a fixed vacuum spectral function, this melting happens dynamically as the medium suppresses dilepton emission by absorbing resonances. In this work, we analyse effective lifetimes of the $\rho$ meson to quantify such collisional broadening within the SMASH approach, for both a thermalized hadron gas and off-equilibrium matter created in heavy-ion collisions.