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The text highlights the challenges of using Bluetooth traffic data for travel time prediction, including:1. Computational requirements: Processing Bluetooth data requires significant computational resources, especially when path information is needed.2. Accuracy and reliability issues: Factors like signal interference, device malfunctions, and limited penetration rates can affect the accuracy and reliability of Bluetooth data, leading to errors and inconsistencies in the collected data.3. Limited information provided: Bluetooth data provides limited information on traffic conditions, which can restrict the effectiveness of travel time prediction models.4. Data filtering and cleaning needs: Bluetooth data often requires filtering and cleaning processes to remove outliers, errors, and inconsistencies.5. Need for integration with other data sources: To improve the accuracy of travel time predictions, Bluetooth data must be combined with other data sources like GPS, video data, or weather information.Overall, while Bluetooth traffic data has advantages like low cost and high sampling rates, its limitations need to be considered when using it for travel time prediction.