Have you ever thought about the limitations of big data usage for travel demand modelling? Here are a few:
1. Certain age group prefer a particular mobile network / smartphone app
2. Big data can’t capture socio-economic attributes so big data alone is not sufficient for building the travel demand model
3. Need to pick the outliers from the big data. Ex: The interaction between shared e-scooter and IoT send / receive the data over mobile network
4. The big data is not always comparable due to changes in technology and other causes
5. Private mobile network companies can change priorities and may stop sharing the data

Source: ITF 2021