Abstract
We analyzed the factors of automobile CO2 emission change calculated with the master data of the origin-destination travel survey by municipalities between 1999 and 2005. CO2 emissions per capita decreased in the municipalities which population was over 50,000 persons, especially in the special wards of Tokyo, on the other hand, the emissions increased in the municipalities which population was less than 50,000 persons. The factors of the decrease were a decrease of travel distance per trip, an increase in fuel efficiency of automobiles, and especially in the major municipalities, a decrease of use and possession of automobiles. The factors of the increase were an increase of the short-distance trips for daily use in the smaller-scale municipalities.
