Safety Planning Resources Resources and tools for conducting predictive safety analysis

Crash Modification Factors / Crash Reduction Factors
NCDOT maintains a list of the crash reduction factors that are to be used for all safety project submittals statewide. The list is updated regularly and reflects information from the FHWA Crash Modifications Factors Clearinghouse as well as the results of safety evaluations that have been conducted by NCDOT staff.

NCDOT Crash Reduction Factors

Predictive Analysis Spreadsheets
NCDOT uses spreadsheet tools that have been developed by national research projects for use in conjunction with the Highway Safety Manual to implement safety performance functions.

Rural two-lane roads
Spreadsheet
Research report
Rural multilane roads
Spreadsheet
Research report (login required)
Urban and suburban arterials
Spreadsheet
Research report (login required)
Urban and suburban arterials (NCDOT developed)
Spreadsheet
Six-lane and one-way arterials
Spreadsheet
Research report
Rural four-lane freeway (includes ramps)
Spreadsheet
Research report
Urban four-lane freeway (includes ramps)
Spreadsheet
Research report
Urban six-lane freeway (includes ramps)
Spreadsheet
Research report
Urban eight-lane freeway (includes ramps)
Spreadsheet
Research report

SPF Calibration Factors
NCDOT has calibration factors to adjust the predictions from the HSM safety performance functions to produce more accurate predictions for North Carolina.

NC SPF Calibration Factors for the Highway Safety Manual, 1^st Edition

NCDOT research projects that produced SPF calibration factors
Development of Safety Performance Functions for North Carolina, NCDOT Research Project Number: 2010-09
Updated and Regional Calibration Factors for Highway Safety Manual Crash Prediction Models, NCDOT Research Project Number: 2016-09
Updated and Regional Calibration Factors for Highway Safety Manual Crash Prediction Models (2016-2019), NCDOT Research Project Number: 2020-27

Crash Proportions
NCDOT has tables that provide a breakdown of crashes by severity and crash type for each major road facility type. These can be used in conjunction with the predictive spreadsheets.

NC Crash Proportion Tables

Intersection Control Selection
NCDOT Safest Feasible Intersection Design (SAFID) Tool

This reference chart, developed internally at NCDOT, provides simple guidance on selecting the safest feasible intersection design for an intersection, given number of lanes and AADT of the intersecting roads.

SAFID Chart

Integrated Project Delivery (IPD) Resources

NCDOT Signal Recommendation Guidance
TIP Project Signal Recommendation Guidelines
TIP Project Signal Recommendation Standard Practices
Traffic Signal Recommendation Memo Template
Traffic Safety Unit Screening Tool

Training Resources for Predictive Safety Analysis
The following links provide resources that may be useful to those who do not have previous experience with predictive analysis.
- FHWA educational videos
- FHWA webinars
- Reading – Road Safety Fundamentals, a textbook from FHWA that covers much of the basic material on predictive safety analysis in Unit 4 - https://rspcb.safety.fhwa.dot.gov/RSF/default.aspx
- Institute for Transportation Engineers review course for the Road Safety Professional exam, one module in particular - Road Safety Fundamentals (4 of 10): Basic Statistics and Predictive Safety (cost: $100-150)

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