This work presents the results of further development of incremental (group contribution) methods for prediction oldie gas transport parameters (permeability (P) and diffusion (D) coefficients) of amorphous glassy polymers. The source of information was a big Database that comprises the P and D values for about 900 polymers. The method of the modified atomic contributions was revisited using much enlarged set of polymeric structures, in addition, a novel one, the bond contribution method, was employed for the first time for predictions of the P and D values of a standard set of gases (He, H-2, O-2, N-2, CO2 and CH4). it was shown that both approaches allow the accurate (improved) predictions of the gas permeation parameters but the latter is more precise (correlation factors R-2 > 0.9). It was also demonstrated that found group contributions permit predictions of the permeability coefficients of random copolymers of different classes. (C) 2015 Elsevier B.V. All rights reserved.