We investigate the dynamics of charge-carriers schemes on high external electric fields in organic semiconductors. Specifically, the critical field strength needed for the transition from subsonic to supersonic regime was determined for solitons and polarons in conjugated polymers, for both trans- and cis-symmetry. Also, the collision between quasi-particles and impurities, at supersonic regime, is investigated. For this purpose it is used a modified Su-Schrieffer-Heeger hamiltonian model in the scope of an Ehrenfest molecular dynamics. The results provide useful information regarding the behavior of the conductivity of conducting polymers measured for different electric fields and bearing different types of impurities. (c) 2012 Elsevier B.V. All rights reserved.