This paper addresses how vehicle designers, analysts, and program managers can exploit the upper bound analysis in a practical fashion to assess vehicle designs, simulations, and experiments to evaluate performance in a way that allows comparison among diverse vehicle designs, quantifies the room for improvement, and helps identify sources of inefficiency (potential targets for improvement) in underbody blast protection performance. We define and describe a set of efficiencies to quantify the effectiveness of various contributions to overall blast protection performance relative to the upper bound. Decomposing the performance into independent contributions isolates the causes or sources of suboptimal performance for analysis and improvement. Understanding the blast protection efficiency of existing vehicles will indicate how much room there is for improvement. The decomposition will further indicate which contributors to blast protection performance have room for improvement. We also account for the contribution of time-varying vehicle acceleration to blast protection performance.