Draft Comprehensive Transportation Plan Update_September 25

ROADWAYS

DRAFT

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 below shows the coefficients used by NCDOT to weight crashes by severity. Severity Description Weight K fatality 76.8 A incapacitating injury 76.8 B evident non-incapacitating injury 8.4 C injury not evident, but complaint of pain or lapse in consciousness 8.4 PDO property damage only 1 ܧ ܲ ܦ ܱ = 76.8( ܭ + )ܣ + 8.4( ܤ + )ܥ + 1(ܲ ܦ ܱ) 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 by Town staff, 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 < 0.4 0.2 points

V/C < 0.6 0.6 points

V/C < 0.8 0.8 points

V/C > 0.8 1.0 point

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. Qualitative Measures SCHOOLS AND COMMUNITY FACILITIES Projects within ½ mile of schools and community facilities were awarded 1 point. Community facilities include parks, community centers, and greenway trailheads. ACTIVITY CENTERS Projects that serve an area designated as Business Activity Center, Neighborhood Activity Center, or Regional Activity Center in the Town’s existing zoning classifications were awarded 1 point. SUPPORTS TRANSIT ROUTES Projects that align with existing and proposed transit routes were awarded 1 point.

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September 25, 2017 Draft