Measuring Workplace Travel Behaviour: Validity and Reliability of Survey Questions

Background. The purpose of this study was to assess the (previously untested) reliability and validity of survey questions commonly used to assess travel mode and travel time. Methods. Sixty-five respondents from a staff survey of travel behaviour conducted in a south-western Sydney hospital agreed to complete a travel diary for a week, wear an accelerometer over the same period, and twice complete an online travel survey an average of 21 days apart. The agreement in travel modes between the self-reported online survey and travel diary was examined with the kappa statistic. Spearman's correlation coefficient was used to examine agreement of travel time from home to workplace measured between the self-reported online survey and four-day travel diary. Moderate-to-vigorous physical activity (MVPA) time of active and nonactive travellers was compared by t-test. Results. There was substantial agreement between travel modes (K = 0.62, P < 0.0001) and a moderate correlation for travel time (ρ = 0.75, P < 0.0001) reported in the travel diary and online survey. There was a high level of agreement for travel mode (K = 0.82, P < 0.0001) and travel time (ρ = 0.83, P < 0.0001) between the two travel surveys. Accelerometer data indicated that for active travellers, 16% of the journey-to-work time is MVPA, compared with 6% for car drivers. Active travellers were significantly more active across the whole workday. Conclusions. The survey question “How did you travel to work this week? If you used more than one transport mode specify the one you used for the longest (distance) portion of your journey” is reliable over 21 days and agrees well with a travel diary.