For bilinearly coupled oscillator models, we examine the statistical relationship between transmission coefficients and committor distribution variances for reaction coordinates obtained by likelihood maximization. Transmission coefficients usually but not always increase as committor distributions narrow for the original version of likelihood maximization. We propose a new inertial version of likelihood maximization that uses velocity information to optimize purely configuration dependent coordinates. The coordinates from inertial likelihood maximization have higher transmission coefficients than coordinates from the original likelihood maximization procedure. Inertial likelihood maximization should be useful for understanding mechanisms of inertial reactions from atomistic simulations. (C) 2012 Published by Elsevier B.V.