Traffic Forecasting Accuracy Assessment Research (2020) / Chapter Skim
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II-40 Conclusions 4.1 Research Questions At the start of this report, the project team identified several research questions, each of which contributed to the project objective of developing a process to analyze and improve the accuracy, reliability, and utility of project-level traffic forecasts. Those research questions related both to the analysis of existing data and to the process to be followed to continue such analyses in the future.
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Conclusions II-41 which had a slope closer to 1 (one) for volumes greater than 30,000 ADT.
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II-42 Traffic Forecasting Accuracy Assessment Research "Forecasting Model") show that, whereas older forecasts do not show a significant bias relative to newer forecasts, they do have a broader uncertainty window.
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Conclusions II-43 The issue of how to treat missing data becomes important when using the quantile regression models. The project team took differing approaches to the model for inference and the model for forecasting.
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II-44 Traffic Forecasting Accuracy Assessment Research The major sources of error on this project were the external traffic forecasts, wherein the actual traffic at external stations was 43% lower than the forecast traffic. Correcting this issue reduced the absolute error to less than 4% for three of four segments, although with this correction actual traffic on the fourth segment remained higher than the adjusted forecast.
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Conclusions II-45 external traffic and travel speed can be important in some cases. However, the project team also found that, even within the small sample of deep dives examined, the reasons for forecast inaccuracy were diverse.
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II-46 Traffic Forecasting Accuracy Assessment Research Forecast Cards and Forecast Cards Data repositories) are waiting to be evaluated after the projects open.
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Conclusions II-47 In relation to these six observations, the project team also considered the following process questions: • What information should be archived from a forecast? • What data should be collected about actual project outcomes?
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