Figure 1.

Commuting time expressed as minutes (total commuting time). (a) Regression of the objective commuting time (y) vs. (x) the self-reported commuting diary time. The regression equation is y = 8.18 + 0.56x. (b) Bland–Altman plot of the total commuting time between self-reported diary time and objective time (y) vs. average of self-reported diary time and objective time (x). The central dotted line represents the mean of differences between the self-reported time measure and the objective time measure; the upper and lower dotted lines represent the upper and lower 95% limits of agreement (mean differences ± 1.96 standard deviations of the differences), respectively.