A universal mass-based index defining energy efficiency of different modes of passenger transport

Reduction in vehicle weight can significantly reduce energy use human transportation. However, to gauge efficiency, and for a particular should be related the number of people being transported while currently there is no convenient means assess this. Here we statistically analyse weight, consumption, carrying capacity occupancy level automobiles, buses, high-speed trains aircraft. Based on analysis inspired by medical body mass index (BMI), have proposed (VMI), defined as I=A(WtvWtp)n, first time enables efficiency assessment different transportations global scale, where n sensitivity parameter A constant theoretically weightless vehicle. We show VMI ranges conclude significant reduction windows achieve their lower limits. The possible limits associated values are also assessed. concept could form basis worldwide standard, useful current drive greener economy.