Master equation approach to the intra-urban passenger flow and   application to the Metropolitan Seoul Subway system
  The master equation approach is proposed to describe the evolution of passengers in a subway system. With the transition rate constructed from simple geographical consideration, the evolution equation for the distribution of subway passengers is found to bear skew distributions including log-normal, Weibull, and power-law distributions. This approach is then applied to the Metropolitan Seoul Subway system: Analysis of the trip data of all passengers in a day reveals that the data in most cases fit well to the log-normal distributions. Implications of the results are also discussed. 
Keumsook Lee, Segun Goh, Jong Soo Park, Woo-Sung Jung, and M. Y. Choi
physics.soc-ph cond-mat.stat-mech physics.data-an