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Center for Transportation Studies

Rural Unsignalized Intersections

The Infrastructure Consortium: Intersection Decision Support

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Projects Components - Task C: Benefit/Cost Analysis

A Benefit:Cost Analysis of proposed technologies to address the IRC intersection crash problem will be performed. Execution of a complete benefit:cost analysis requires the execution of the subtasks identified below:

SUBTASK C1: IDENTIFY RELEVANT TECHNOLOGIES, REVIEW OF LITERATURE

In this task, emerging technologies (radar, vision, microloops, etc.) and traditional engineering approaches (intersection redesign, grade separation, improved traffic control devices (signs, signals, markings)), will be reviewed and analyzed as potential solutions to the IRC intersection problem. To fully evaluate emerging technologies, comparisons with existing solutions are necessary.

SUBTASK C2: DEVELOP BENEFIT COST FRAMEWORK

A benefit - cost framework must be developed to provide a fair comparison of disparate technologies. A set of stylized scenarios for which the new technologies and traditional engineering solutions can be applied will be developed. These include application to a single intersection, as well as to the entire class of a particular intersection nationally. We will assume in our benefit cost analysis a fully deployed system.

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SUBTASK C3: ESTIMATE LIFESPAN OF TECHNOLOGY

A technology with a short shelf life may need to be replaced twice, while a long-lasting road based intersection improvement may have a 30-year lifespan. This will affect the resultant benefit cost calculations.

SUBTASK C4: ESTIMATE COSTS OF TECHNOLOGY

This element will estimate the fixed and variable costs of each identified technology. In particular, the key technologies (i.e., Radar, GPS, and Wireless communication) will be addressed in this study, the goal being an estimate of the costs of these technologies as applied to a particular IDS.

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SUBTASK C5: ESTIMATE BENEFITS OF COUNTERMEASURES

The work proposed herein will examine the benefits of fully deployed systems. Assuming that the technology upstream of the driver interface components are similar, IDS approaches are differentiated by the type of user interface. For this task, safety, mobility, societal benefits of countermeasures of these two approaches will be studied on their own merits, and on a comparative basis.

SUBTASK C6: LIFECYCLE ANALYSIS

A full benefit-cost analysis for each technology/engineering solution over a fixed period of time across several scenarios will be developed. The net present value and B/C ratio for each alternative will be prepared. Sensitivity testing will be conducted to determine whether results are robust to small and large changes in inputs.

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SUBTASK C7: RECOMMEND COUNTERMEASURES

This approach considers the benefits and costs to three effected groups: system users (travelers), the agency deploying the technology (a state DOT for instance), and the community at large who may benefit from reduced negative externalities. Given the benefits in terms of lives saved, injury reduction, time savings, and property damage avoided along with the costs of installation of the improvement under those conditions, the cost- effectiveness can be calculated. This task will produce a working paper describing the benefit model and summarizing the costs. The full life-cycle cost-benefit analysis method will be presented for specific cases and the methodology described to enable it to be extended by practicing engineers.

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SUBTASK C8: ANALYZE INTER-TECHNOLOGY EFFECTS

This element will review studies and models to understand the inter-technology effects. The sum of the benefits of each technology alone may be more or less than the benefits of those technologies when deployed together. To develop effective deployment strategies, the interaction of elements of the IDS system must be understood.

SUBTASK C9: DETERMINE PERFORMANCE METRICS

At a minimum cost, lives and injuries avoided, and property damage must figure into this analysis. Determination of precisely how those elements are combined is the purpose of this component.

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SUBTASK C10: DEVELOP COST:PERFORMANCE MODELS

A set of cost-performance models, describing how much benefit can be gained for investment in the technology, subject to the presence or absence of other technologies will be estimated. These models will feed optimization subtask (subtask C12) below.

To support the development of the cost:performance models, documented cost:performance models for individual technological components must be provided for inclusion in the system model.

SUBTASK C11: ANALYZE SYNERGIES

The presence or absence of related technologies may be an important factor in the importance of any particular technology, and will play a role in the development of a deployment strategy. This step will analyze the cost : performance models.

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SUBTASK C12: OPTIMIZE COUNTER-MEASURE COMBINATION

An economic simulation model will be developed which integrates the cost-performance models and interaction models, and considers a number of cases. These cases will be analyzed and an optimal combination of countermeasures will be developed. The optimization will be driven by the performance metrics developed above.

SUBTASK C Deliverables:A framework/methodology for determining benefit:cost ratio for rural intersection decision support systems.

Working papers, mathematical models, and a comprehensive final report will document the approach and results of the benefit:cost task.

SUBTASK C Duration:17 Months.

Link to state pooled fund:This task is linked to the state pooled fund by the fact that the optimization process (Subtask C12 above) will provide an optimal system design. A secondary benefit is that states who chose to deploy can use the benefit:cost analysis to develop their individual deployment strategies.

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