The aim of this study is to analyse the diffusion effect of passenger vehicles that achieved the fuel consumption standard under the Top Runners Approach towards the improvement of stock-based fuel consumption in actual use (actual fuel consumption). In order to investigate the actual fuel consumption with high statistical reliability, we have put focus upon voluntary reported fuel consumption log data collected from all over Japan for 54 months by a certain mobile phone contents provider and have established an actual fuel consumption database of passenger vehicles. The results of statistical analyses using the database show that actual fuel consumption can be explained by vehicle weight and that actual fuel consumption of gasoline-fuelled passenger vehicles is significantly improving every year compared with that of FY2001. The validity of the actual fuel consumption obtained from the database is confirmed by comparing with the actual fuel consumption estimated from existing transport statistics.
