When scoping a project for traffic forecasting, the appropriate forecasting methods should be identified based on the project scoping limits, data requirements, project timeline, and stakeholder needs. The steps to determine applicable forecasting methods are listed, as follows:
The purpose and need of the project should be clearly defined, including the specific transportation issues that the project aims to address. This will help determine what type of forecasting methods are applicable.
The data needs to support the traffic forecasting should be identified, including historical traffic data, demographic information, land use data, and information on planned development and transportation projects. Traffic and forecasting data from other traffic engineering-related studies in and around the project area could also be considered.
There are several forecasting methods available, including travel demand models, traffic growth trends, and land use data analysis. Each method has its own strengths and weaknesses, and the appropriate method will depend on the project scope and data requirements.
The available forecasting methods should be evaluated based on their suitability for the project. This may involve considering factors such as accuracy, reliability, ease of use, and the ability to incorporate different types of data. Based on the evaluation, the appropriate forecasting method or combination of methods can be selected for the project.
There are different types of forecasting methods, each with its own strengths and weaknesses. The method using travel demand models involves analyzing the relationship between transportation supply and demand, and predicting how transportation supply and demand changes will impact future traffic patterns. Trend analysis involves identifying relationships between variables, such as traffic volumes in terms of “time of day” or “day of week,” and can be used to predict future traffic patterns based on historical data. The appropriate method will depend on the specific forecasting issue and data available. To determine which forecasting method to use, it is important to consider the following factors:
- Data availability and quality: The forecasting method used should be appropriate for the type and quality of data available. Some methods using demand models require more data than others, and some using collected data are more sensitive to the quality of the data.
- Scope and complexity of the forecasting issue: The forecasting method used should be appropriate for the scope and complexity of the project purpose and need. Some methods applying traffic growth rates are more suitable for simple forecasting issues of intersections, while others are more suitable for complex issues, such as corridor and subarea studies.
- Analysis years: The analysis years for the forecasting should be considered. Methods like trend analysis are better suited for short-term forecasting, while other methods, like travel demand models, are better suited for long-term forecasting.
- Accuracy and reliability: The accuracy and reliability of the forecasting method should also be considered. Some methods are more accurate and reliable than others, and the appropriate method will depend on the level of accuracy and reliability required for the specific project's purpose and need.
By considering these factors, the appropriate forecasting method can be selected for the specific forecasting scope. It may also be useful to use a combination of methods to take advantage of their strengths and overcome their weaknesses.