Making Transit Reliability Benefits Accessible to Engineers

by | Mar 28, 2016 | Uncategorized

Ben Rommelaere will be presenting a paper at the ASCE International Conference on Transportation & Development (ICTD 2016 June 26-29 2016). The two of us wrote the paper and I’ll post a link to the published paper after the conference in July. In the meantime here is the abstract and summary.

Transit construction

Abstract Advances in measuring the intangible costs and benefits of transportation are being made but economic cost-benefit models used to analyze transportation infrastructure projects have not kept up. There are new benefit categories that existing transportation cost-benefit models do not include. One example is the benefit of travel time reliability. This paper summarizes the results of 30 studies of reliability and synthesizes them into a reliability ratio that can be used in transit cost-benefit analysis. By interpreting and standardizing reliability research the paper shows how cutting edge transportation research can be made available to engineering and planning professionals in their planning and design decisions. The value of reliability is implemented in a cost-benefit and risk analysis model and is freely available as a spreadsheet from the authors.

Introduction and SummaryThe life of a transit project can easily last for decades before construction is even scheduled. Once past the feasibility stage, some plans spend years in the planning phase, and usually years in design.

Economists are often involved in transit projects by advising on, using cost-benefit analysis, the early go/no go decision. Sometimes, if they behave themselves and prove useful to the transportation planners, economists may be asked back to do an assessment of options, such as which alignment or type of transit delivers the most value.

The professionals that economists rely on to provide input into their models are the engineers. Engineers have access to all of the project data, the projected quantity of labor and material used, their costs, the schedule, who will benefit and who will be hurt by the project. First in and last out, engineers make thousands of decisions long after the economists have moved on to their next consulting gig. It is this myriad of choices and decisions that are made by the engineers that determine the real value of a project. How stormwater runoff is managed on the transit corridor, whether active transportation is encouraged, how many trees are planted, and which neighborhoods are served determine the sustainability, equity, environmental and public benefits of the project.

Through standardization of the economic methodology as well as much of the data required for the cost-benefit analysis infrastructure can be automated and used much more extensively and effectively in transportation planning and design decisions. Automating the cost-benefit analysis process means that engineers, rather than economists, can use cost-benefit analysis for all the decisions that influence the project. By giving those who best understand the project and access to the most data is more efficient, cheaper, and will result in better decisions.

Advances in measuring the intangible costs and benefits of transportation are being made but economic cost-benefit models used to analyze transportation infrastructure projects have not kept up. There are new benefit categories that existing transportation cost-benefit models do not include. One example is the benefit of travel time reliability. Research on this benefit category needs to be standardized to make it accessible to transportation planners so that they can use it in decision-making. This paper summarizes the results of 30 studies of reliability and synthesizes them into a reliability ratio that can be used in transit cost-benefit analysis. By interpreting and standardizing reliability research the paper shows how cutting edge transportation research can be made available to engineering and planning professionals in their planning and design decisions.

The value of reliability is implemented in a cost-benefit and risk analysis model and is freely available as a spreadsheet here. Documentation is also available.

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