3 Roadway Element
Recommended Intersection Projects Intersections can have as large an influence on the overall travel experience as street design, and many elements of intersection design can be in tension with each other, requiring careful planning and evaluation. Accommodations for left turning vehicles often have the most influence on intersection operations, but space constraints may limit their inclusion or shorten the needed length for queuing vehicles. In addition to impacting traffic flow, intersection design has an out-sized impact on safety for drivers, bicyclists, and pedestrians. According to the FHWA (The Federal Highway Administration), roughly one-quarter of traffic fatalities and about one-half of all traffic injuries in the United States are attributed to intersections. The Fuquay-Varina 2040 CTP leverages existing safety and traffic data, as well as feedback from the community, to screen and identify intersections in need of improvement. The CTP does not identify specific recommendations for each intersection, as further study and detailed analysis will be needed to identify the best combination of geometric and control solutions. This analysis is often known as Intersection Control Evaluation (ICE) and is described in greater detail below. Intersection Control Evaluation Intersection Control Evaluation (ICE) is a performance-based process and framework used to consider alternatives and identify optimal solutions for intersection improvements. ICE is applicable to most intersection improvements. The checklist below can help determine if an ICE should be pursued.
Step 1: Scoping and Screening Step 1 determines potential alternatives that meet the purpose and need of the project. The following data is needed to identify potential alternatives: • Crash assessment • Traffic volumes for safety and operational analysis
• Planning-level cost estimates • Right-of-way/footprint needs
• Environmental impacts • Stakeholder feedback Screening Alternatives Filter through the alternatives and narrow the pool to two (2) to three (3) options by asking: does the alternative... • Address the project purpose and need? • Improve safety? • Improve operational performance? • Consider multiple modes including pedestrians and bicyclists? • Fit the context of the site in terms of land use characteristics? • Meet the needs of directly affected stakeholders? Potential design alternatives are provided on the following page. While not comprehensive, the list includes many of the most common alternatives, as well as several innovative solutions. Step 2: Alternative Selection Step 2 focuses on determining the preferred alternative based on a benefit-cost analysis, outcomes from detailed evaluations conducted during typical preliminary engineering activities, and a qualitative assessment. Benefit-Cost Analysis In general, ICE analyses focus on five (5) performance measures to calculate the benefit-cost ratio.
When to Conduct ICE • New intersection or intersection modification
• Safety improvement • Congestion mitigation • Full access median opening • Intersection signalization
NCHRP Report 1087: Guide for Intersection Control Evaluation provides further information on intersection control evaluation, as well as methods for screening and analysis.
• Corridor widening/reconstruction • Multimodal facility enhancement When NOT to Conduct ICE • No change to intersection geometry or control • Converting 2-way stop to 4-way stop • Changing a full median opening to a directional median opening • Adding right-turn lanes • Changing signal phasing/timing • No alteration of footprint
1. Safety 2. Delay (travel time reduction savings) 3. Emission reductions (optional)
4. Operations and maintenance 5. Initial capital cost
Cost Performance Measures calculate the added costs of an alternative compared to the existing condition
Benefit Performance Measures calculate the benefits of an alternative compared to the existing condition
An ICE is a two-step process of screening potential intersection design alternatives and selecting the ultimate preferred alternative.
Additional Assessment Additional quantitative and qualitative elements to consider when determining the preferred alternative(s) include:
• Environmental impacts • Right-of-way impacts
• Multimodal accommodations • Public opinion and input
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Town of Fuquay-Varina
2040 Comprehensive Transportation Plan
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