Transportation planning and design require different levels of detail with respect to forecasting travel behavior, demand, and use. Whereas many planning decisions can be supported by typical outputs of a four-step travel demand model, these same outputs are insufficiently precise to support many of the decisions being made during detailed project development and design.
Truck traffic forecasting is often conducted as a post process of the data results from a travel demand model or is conducted using commodity flow or other economic and statistical models. Yet, a variety of specific decisions regarding the placement, quantity, length, and geometry of facilities to support a specific volume and type of truck traffic would benefit from more specific data, methods, and techniques for using truck traffic forecasts in project design.
Among the limitations of typical travel forecasting models are the ability to predict the specific volumes, weights, and movements of trucks on highways. Truck traffic imposes specific design requirements to accommodate their unique weights and configurations. Transportation agencies and freight distributors need to assess truck travel in different contexts, including but not limited to long-haul goods transportation, local, and last-mile freight deliveries.
State departments of transportation (DOTs) and modeling professionals are responding to these challenges by creating more accurate and responsive models and model applications, particularly as the research and development of modeling methods and techniques continue to advance. Nevertheless, the transportation industry is not uniform with respect to its technical knowledge, capabilities, budgets, or other resources needed to develop and apply sophisticated models and decision tools to support project design decision-making. While some state DOTs have the resources to supplement in-house staff or hire outside experts to conduct model runs and analyses, many others simply do not have that capacity.
The objective of this research is to develop a guide to assist state DOTs and other agencies in the selection and use of forecasting models, applications, procedures, tools, and techniques needed to support project design.
At a minimum, the research team shall:
1. Identify and evaluate the range of existing and emerging technical approaches, data sources, models, model applications, and tools available to generate and apply truck traffic forecasts to support project design;
2. Identify gaps and needs for improvement in those applications, tools, and techniques within the context of design decision-making;
3. Compare (quantitatively) the accuracy of new methods to traditional methods;
4. Provide user-friendly instructions on the appropriate selection and use of specific model applications, tools, or techniques during project design; and
5. Refer to the truck classifications 5-13 provided in the Federal Highway Administration Traffic Monitoring Guide, updated October, 2016.
Detailed implementable results are expected from this research. The proposal shall define a set of deliverables for conveying the research results and providing direction to the targeted audience on the selection and application of truck traffic forecasts to support design decisions.
The research plan should be conducted in two phases and presented as a set of tasks with deliverables identified to correspond with major milestones of this project. At a minimum, the research plan shall (1) include a kick-off web conference with NCHRP project panel members; (2) articulate a process and method for achieving the research objective of this project; (3) be divided into two logical phases with clear outcomes and verifiable results that encompass all specific detailed tasks for each phase; and (4) include adequate time for panel and staff reviews of all milestone deliverables.
Phase I of the research should stipulate a specific set of tasks that will be undertaken to generate a comprehensive understanding of the industry state of practice with respect to the conduct and use of truck traffic forecasting to support project development and design. The research should include efforts to address the full range of issues affecting the development and use of truck traffic forecasts in project development and design. These include but are not limited to issues with data sources, data collection, model structures, model applications, post processing applications, and the quality of truck forecasts that emerge from these products and processes with respect to their accuracy and use during project development and design.
In developing the research approach, consideration should be given, but not limited to the following tasks:
Task 1. Conduct a literature review of available literature on truck traffic forecasting methods and applications, including completed NCHRP and related research. The proposals shall demonstrate the research team’s knowledge of the literature and the state of the practice with respect to the research topic.
Task 2. Synthesize industry state of practice that identifies gaps in knowledge and effective practice in truck travel forecast to support design decisions. This synthesis shall include information on data, model designs, forecasting techniques, and use of truck traffic forecasting to support transportation project development and design. Industry surveys, interviews, workshops, case studies, or other activities may be appropriate methods to engage agency staff and collect data to support this assessment.
Task 3. Summarize the appropriate use and application of the methods and practices of truck traffic forecasting in design identified in the data collection activities identified above. The summary shall include but not necessarily be limited to the quality and availability of input data, the strengths and weaknesses of various modeling methods and techniques to support project design decisions, as well as potential issues or challenges with the implementation of the methods.
Task 4. Develop an interim report that summarizes the activities, analysis, and other conclusions drawn from the data collection and analysis conducted in Phase I. This report should set forth a clear research plan of activities and tasks to be conducted during Phase II of the research project. The report shall include a description and proposed outline of the guide and any additional recommended products to be developed during Phase II. Lastly, the report should include a clear approach to preparing and testing the products for their application by the transportation industry.
Work in Phase II is to be executed as described in the NCHRP approved Phase II work plan.
The research team is strongly encouraged to propose methods to engage the targeted audiences to share and validate the quality of the guide. For example, the research team may propose to hold a virtual workshop to share and test draft products for their effectiveness and utility, as budget and schedule permit.
Deliverables shall at a minimum include:
A guide to the design and application of truck traffic forecasting methods to support design.
An implementation plan for the dissemination and use of the final product or products of this research project by agency staff.
A contractor’s final report detailing the full research process and results.
STATUS: Proposals have been received in response to the RFP. The project panel will meet to select a contractor to perform the work.