Till Örebro universitet

Purpose:

There is a need for accurate, reliable, and feasible methods for determining route distances in physically active transportation. The aim of this study, therefore, was to scrutinize if distances of commuting routes drawn by physically active commuters and measured with a digital curvimetric distance measurement device could serve such a purpose.

Methods:

Participants were recruited when walking or bicycling in the inner urban area of Stockholm, Sweden. Questionnaires and individually adjusted maps were sent twice to the participants (n = 133). Commuting routes from home to work were drawn on the maps. These were measured using a digital curvimetric distance measurer that was carefully controlled for validity and reproducibility. Marked points of origin and destination were checked for validity and reproducibility using stated addresses and address geocoding systems. Nineteen participants were followed with a global positioning system (GPS) to control for validity of drawn routes. An analysis of the effect on distance measurements of any deviations between GPS route tracings and drawn routes was undertaken.

Results:

No order effects were noted on distance measurements, and the test-retest intraclass correlation coefficient was 0.999 (P ≤ 0.001). The map markings of route origins and destinations were accurate and reproducible. GPS tracings of actual commuting routes taken (n = 19) as displayed in six cases had slight deviations from the routes drawn by the commuters on maps. However, these deviations played an insubstantial role (0.4%) for the distances measured.

Conclusion:

When physically active commuters draw their commuting routes on maps, they create a valid and reproducible basis for route distance measurements. In combination with an accurate digital curvimetric distance-measuring device, a potential criterion method for measuring the commuting route distance is established.

Distance is a variable of pivotal importance in transport studies. Therefore, after checking the validity of a potential criterion method for measuring active commuting route distances, this method was used to assess the validity and reproducibility of four methods of approximating the commuting route distances covered by pedestrians and bicyclists. The methods assessed were: self-estimated distance, straight-line distance, GIS shortest-route distance, and GPS-measured distance. For this purpose, participants were recruited when walking or bicycling in Stockholm, Sweden. Questionnaires and individually-adjusted maps were sent twice to 133 participants. The distances of map-drawn commuting routes functioned as criterion distances. The participants were also asked to estimate their distances. The straight-line distance between origin and destination was measured using map-drawn routes. The shortest route between home addresses and workplace addresses was calculated with three GIS algorithms. Eighty-six trips were measured with GPS. The main results were that test–retest intraclass correlation coefficients (ICC) exceeded 0.99 for all methods, except for self-estimated distance (ICC = 0.76). No ordereffects existed between test and retest. Significant differences were, however, noted between criterion distance and self-estimated distance (114 ± 63%), straight-line distance (79.1 ± 10.5%), GIS shortest route (112 ± 18 to 121 ± 22%) and GPS distance (105 ± 4%). We conclude that commonly-used distance estimation methods produce systematic errors of differing magnitudes when used in a context of active commuting in suburban and urban environments. These errors can at average level be corrected for, whereas individual relative errors will remain.

Background

Knowledge concerning active commuting behaviours is meagre. Therefore, we have previously developed a criterion method for measuring commuting distance. Here we study the reliability of selfreported duration, red-light stops, velocity and weekly trip frequency per month over the year. We also assess all these variables in men and women, walking or cycling the whole way from home to work or school in a metropolitan setting.

Methods

Test-retest reproducibility was studied in a street-recruited sample of adult commuters in Greater Stockholm, Sweden (n = 70). Another group of adult commuters was recruited via advertisements in two newspapers (n = 1872). They all received a questionnaire and individually adjusted maps to draw their normal commuting route.

Results

The reproducibility of the different variables varied from moderate to almost perfect. Three different modality groups were identified in both men and women. The median durations of single mode commutes varied between 25 and 30 minutes. Single mode pedestrians had a high weekly trip frequency over the year, 7 to 8 trips, and a median distance of 2.3 km. The median single mode bicyclist did not cycle during the winter, but had a high weekly trip frequency, 6 to 9 trips, during the summer period, with a distance of 9 km for men and 6.7 for women. The distances of dual mode commuters, who alternately walk and cycle, were about 2.8 km. Their weekly cycle trip frequency mimicked the single mode cyclists‘. Primarily during the winter they substituted cycling with walking. Through the active commuting per se, the median single mode pedestrians and dual mode commuters met or were close to the recommended weekly physical activity levels of 150 minutes per week most of the year, whereas the single mode cyclists did so only during the summer half of the year. Some gender differences were observed in distances and velocities.

Conclusions

Distinctly different types of active commuting behaviours exist in a metropolitan setting and depend on mode choice and gender. Future studies on active transport are recommended to assess both walking and cycling over the whole year.