Comprehensive Transportation Plan - March 2019
PROJECT SHEETS
PROJECT SHEET DATA This page outlines further information about the data displayed in the following project sheets. Where applicable, the data source,
definitions, and process are described. Traffic Volumes (VPD)
Traffic volumes for the project sheets were obtained from the regional travel demand model. Volumes for the year 2010 were obtained from the Capital Area Metropolitan Planning Organization’s Triangle Regional Model for the current 2010 base year. Traffic volumes for the year 2040 were obtained from a final run of the CTP network and considers the construction of the proposed project and the associated improvements. Congestion (V/C Ratio) Congestion values for the project sheets were obtained from the regional travel demand model. Congestion values for the year 2010 were obtained from the Capital Area Metropolitan Planning Organization’s Triangle Regional Model for the current 2010 base year. Anticipated congestion for the year 2040 was obtained from a final run of the CTP network and considers the construction of the proposed project and the associated improvements. Congestion is identified by using volume-to-capacity (V/C) ratios. V/C ratios are calculated by dividing the traffic volume of a roadway segment by the theoretical capacity of the roadway. Although V/C can be tied to level of service (LOS), V/C allows for a more specific analysis. The result is a universal quantitative measurement. The information provided in Table C-1 provides an overview of volume-to-capacity ratios and descriptions of each category.
Table C-1: Understanding Volume-to-Capacity Ratios CATEGORY DESCRIPTION
A roadway with a V/C less than 0.50 typically operates with free-flowing conditions and is underutilizing available roadway capacity.
Very Below Capacity V/C < 0.50
A roadway with a V/C between 0.50 to 0.85 typically operates with efficiency and is not considered congested.
Below Capacity V/C = 0.50 to 0.85
As the V/C nears 1.0, the roadway is becoming more congested. A roadway approaching congestion may operate effectively during non-peak hours but be congested during peak travel periods. Roadways operating at capacity or above capacity are heavily congested during peak periods and moderately congested during non-peak periods. A change in capacity due to incidents greatly impacts the travel flow on corridors operating within this V/C range.
At Capacity V/C = 0.85 to 1.00
Above Capacity V/C > 1.01
Street Hierarchy The street hierarchy reflects potential changes to the transportation network discussed in Chapter 3 . Street hierarchy allows the Town to balance competing interests between design features, travel modes, and available rights-of-way. To read more about the different street
hierarchies see Chapter 3: Roadways . Planning Cost Estimates
Planning cost estimates were obtained using NCDOT’s per mile cost tables and approved methodology for long range planning. This method is to prepare planning level estimations only, and are subject to change as the project moves into preliminary engineering, design, and delivery phases. The estimates shown are reflective of construction costs, estimated right-of-way costs, and a percentage based estimate of engineering and contingency costs. Step 1 : Multiply the proposed typical section by the total project length. Step 2 : Add the costs for bicycle and pedestrian facilities, bridges, and grade separations. Step 3 : Add the cost for water and sewer line relocations. Cost estimates are determined by multiplying the project length by the NCDOT- provided costs per linear foot.
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