OBJECTIVE
The objective of this research was to develop a spreadsheet-based tool that can be used by an engineer to compare the life-cycle costs of alternative designs for new and existing intersections. The tool will be applicable to the following types of intersections: stop-controlled, traffic signal, roundabout, and innovative designs.
STATUS
NCHRP Web-Only Document 220: Estimating the Life-Cycle Cost of Intersection Designs and the Life-Cycle Cost Estimation Tool are now available. The
distribution webpage also includes six case studies illustrating use of the LCCET. A
TRB Webinar is scheduled for April 19, 2016.
BACKGROUND
Roadway infrastructure is costly to build, manage, repair, and replace. Historically, asset investments have been based on expedient design and lowest construction cost. State and local transportation agencies are increasingly considering costs and impacts throughout the life of the project in making investment decisions (see NCHRP Report 483: Bridge Life-Cycle Cost Analysis as an example). Intersections are key components of the roadway infrastructure and the intersection design can significantly impact the maintenance and other costs that accrue after construction. In many cases, costs during the intersection’s life may be shared between different transportation agencies. In addition to direct agency costs, societal costs are significant at intersections; particularly crashes, delays, and emissions. There can also be economic impacts on nearby businesses. A life-cycle cost analysis is useful in bringing together factors that can be monetized but there are often agency or community goals that need to be considered in the design of the intersection. These may include a desire to improve the walkability of the network, to preserve the historical context, or to avoid taking a particular property. An agency’s budget may also constrain the number of feasible designs. The results of a life-cycle cost analysis should inform, but not dictate, the design decisions related to an intersection. There are many methods and data sources for estimating the costs associated with an intersection’s design. These methods and data sources are continually being updated and improved, but a tool is needed to take the information provided by them, determine the life-cycle costs in a consistent and transparent manner, and present the results in a way that facilitates comparison of design alternatives.
TASKS
Task 0. Prepare Amplified Research Plan.
Task 1. Prepare a technical memorandum describing the methodology that will be the foundation for the tool and justifying its use over other approaches. The technical memorandum should discuss how the following issues will be address: (a) different types of costs, (b) different life cycles for the alternative designs, (c) rationalization of different performance metrics (e.g., control delay and total delay), (d) marginal analysis of alternative designs, and (e) future inclusion of new types of intersections.
Task 2. Prepare a technical memorandum describing the types of costs that will be incorporated into the tool. These should include, but not be limited to, engineering, right-of-way, construction, maintenance, user costs (including during construction), safety, environmental impacts, and impacts on businesses.
Task 3. Prepare a technical memorandum describing likely data sources for the user to develop the cost estimates that will be entered into the tool (e.g., Highway Safety Manual, local real estate values).
Task 4. Prepare mockups of the user interface and outputs, including graphical presentations of the analysis results. Outputs should address the needs of planners, engineers, decision makers, and the public.
Task 5. Prepare a plan for validating the usefulness of the tool by working with a few agencies to analyze specific intersections or groups of intersections.
Task 6. Prepare an interim report summarizing the key findings from Tasks 1 through 5 of the research effort and providing a detailed work plan for completing the project. Meet with the project oversight panel to review and refine the interim report.
Task 7. Prepare the economic analysis spreadsheet-based tool that has undergone a quality control process. User documentation should be embedded into the tool. It is expected that the tool will be freely available on the TRB website and that users will be able to customize it to meet their own needs, particularly storing the own default parameters.
Task 8. Prepare illustrative case studies based on the validation work. Present a plan for disseminating the case studies to demonstrate the tool’s value to prospective users and facilitate implementation.
Task 9. Prepare a final report that summarizes the work that was done and includes documentation for the tool.
Task 10. Prepare a TRB webinar presenting the tool to prospective users.
DELIVERABLES
1. A technical memorandum describing the methodology that will be the foundation for the tool and justifying its use over other approaches. The technical memorandum should discuss how the following issues will be addressed: (a) different types of costs, (b) different life cycles for the alternative designs, (c) rationalization of different performance metrics (e.g., control delay and total delay), (d) marginal analysis of alternative designs, and (e) future inclusion of new types of intersections.
2. A technical memorandum describing the types of costs that will be incorporated into the tool. These should include, but not be limited to, engineering, right-of-way, construction, maintenance, user costs (including during construction), safety, environmental impacts, and impacts on businesses.
3. A technical memorandum describing likely data sources for the user to develop the cost estimates that will be entered into the tool (e.g., Highway Safety Manual, local real estate values).
4. Mockups of the user interface and outputs, including graphical presentations of the analysis results. Outputs should address the needs of planners, engineers, decisionmakers, and the public.
5. A plan for validating the usefulness of the tool by working with a few agencies to analyze specific intersections.
6. The economic analysis spreadsheet-based tool that has undergone a quality control process. User documentation should be embedded in the tool. It is expected that the tool will be freely available on the TRB website and that users will be able to customize it to meet their own needs, particularly storing their own default parameters.
7. Illustrative case studies based on the validation work. Proposals should describe how these case studies will be disseminated to demonstrate the tool’s value to prospective users and facilitate implementation.
8. A final report that summarizes the work that was done and includes documentation for the tool.
9. A TRB webinar presenting the tool to prospective users.
