How comparable are mobile phone data and travel survey data?

This work uses 2017 mobile phone-based origin-destination matrices to derive an average of 1.9 trips per day for the province of Liège. According to the national online mobility survey from 2016 to 2017 called MONITOR, Belgians make an average of 2.2 trips per day, which is comparable with 1.9. The additional comparative analysis includes exploring the hourly net flow balance, which refers to the research area’s inbound and outbound trip differences. As a result, the net flow reaches a balance for mobile phone data and the travel survey during a full day and is close to zero. After that, this work normalizes daily trips by origin so that the sum along the columns (destinations) equals one and builds a distribution difference matrix. A coefficient of determination (R2) of 0.41 is derived. Finally, a match is found at night when comparing the mobile phone-extrapolated population and official population statistics. However, for most of the districts, the number of residents exceeds the number estimated by MPD during the day, which can be explained by the fact that not all residents own mobile phones and be active during the day.