DRAFT Comprehensive Transportation Plan Update: 2/23/2018 version

Roadway Project Prioritization

The assessment of roadway projects for the Town of Morrisville Comprehensive Transportation Plan Update includes both

quantitative and qualitative metrics. The metrics used were defined using feedback from Town staff, the Morrisville Planning and Zoning

Board, CAMPO, and NCDOT. National resources such as Transportation for America’s The Innovative MPO and their Transportation

Performance Measures: 2017 Survey were consulted to pull from national best practices. In addition to each metric, the importance of each

metric to the prioritization process and how much weight each should carry was evaluated through a coordinated effort including Town

staff, the Morrisville Planning and Zoning Board, and the public. The following sections define the metrics used in the prioritization process.

RELATIONSHIP TO GUIDING PRINCIPLES

During the development of prioritization criteria, the relationship to the Plan’s guiding principles was closely considered. Each of the

prioritization criteria identified responds to one or more guiding principles. The relationship between prioritization criteria and guiding

principles is detailed in Figure 5-2 .

Figure 5-2: Prioritization and Guiding Principles Relationship

APPLICABLE GUIDING PRINCIPLES

APPLICABLE GUIDING PRINCIPLES

PRIORITIZATION CRITERIA

PRIORITIZATION CRITERIA

Schools and Community Facilities

Crash History

Existing Volume to Capacity Ratio

Activity Centers

Volume to Capacity Reduction

Supports Transit Routes

QUANTITATIVE METRICS Crash History To ensure that project recommendations best serve areas with existing safety concerns, crash data from June 2013 to May 2016 was

analyzed relative to crash severity and frequency. Crash frequency includes a raw count of crashes along roadway project segments and

within 300 ft. of intersection projects.

The crash severity metric was calculated using NCDOT’s methodology that converts each crash to a “property damage only” equivalency.

This is called the equivalent property damage only (EPDO) index, and gives greater weight to more severe crashes. The Table 5-7 shows

the coefficients used by NCDOT to weight crashes by severity.

Table 5-7: NCDOT Crash Weighting Coefficients

SEVERITY DESCRIPTION

WEIGHT

K

fatality

76.8 76.8

A

incapacitating injury

B

evident non-incapacitating injury

8.4 8.4

C injury not evident, but complaint of pain or lapse in consciousness

PDO

property damage only

1

= 76.8( + ) + 8.4( + ) + 1( )

Existing Volume to Capacity Ratio Existing volume-to-capacity ratios (V/C) were scored using the Locally Administered Projects Program (LAPP) methodology. The existing V/C

for each linear project was obtained from the 2010 Triangle Regional Model and scaled using a point system. For new location roadways,

parallel facilities that would be improved by the project were identified and the V/C of the parallel facility was used. The scoring system is

defined below.

V/C < 0.2

0.0 points

V/C < 0.8

0.8 points

V/C < 0.4

0.2 points

V/C > 0.8

1.0 point

V/C < 0.6

0.6 points

Volume to Capacity Reduction Each linear project is scored based on the volume-to-capacity reduction from year 2010 to 2040. V/C ratios for the existing year were

obtained from the approved regional travel demand model (Triangle Regional Model v5) base year 2010 model network with 2040 socio-

economic data, and future year V/C ratios were obtained from a 2040 full build-out model.

5-8 | P A G E D R A F T | 0 2 / 2 3 / 2 0 1 8