Explaining the Evolution of Passenger Vehicle Miles Traveled

The similarity of the predicted VMT and the estimated VMT suggests that demographics and economic characteristics explain the slowdown of VMT growth in the 2000s and the recovery of VMT growth in the 2010s. [...] Second, the variables included in equation (3) as the basis for the decomposition reflect a balancing between the desire to include as many variables as possible—which increases the fit of the equation and reduces the influence of omitted variables—with the need to combine the CPS and NHTS data. [...] Finally, changes in the number of workers per household reduced average VMT per household during the 2000s and 17 Resources for the Future Leard, Linn, and Munnings increased VMT per household in the 2010s; although not shown in the table, the increasing number of households further contributed to the national VMT growth in the 2010s. [...] Despite the differences in the variables used in equation (3) and the differences between NHTS and CPS household counts (see Figures 3 and 4), the overall conclusion is the same as the baseline regarding the contribution of demographics and economic characteristics to VMT dynamics. [...] In particular, the aging of the population, the economic downturn, and changes in the income distribution, as well as changes in driving habits, could explain the slowdown of VMT growth in the 2000s.