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Traffic Safety Unit
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NCDOT Traffic Safety Unit Pre-Construction Conference May 2018 - - PowerPoint PPT Presentation
NCDOT Traffic Safety Unit Pre-Construction Conference May 2018 - - PowerPoint PPT Presentation
NCDOT Traffic Safety Unit Pre-Construction Conference May 2018 Traffic Safety Unit 2016 Crash Facts Statewide Summary 2 Traffic Safety Unit Mission Reduce Crashes and/or Severity of Crashes 3 Traffic Safety Unit Unit Work Groups /
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Traffic Safety Unit
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Mission
Reduce Crashes and/or Severity of Crashes
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Traffic Safety Unit
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Unit Work Groups / Areas
Traffic Safety Specialist Highway Safety Improvement Program Regional Field Operations Safety Evaluation Safety Planning Mobility and Safety Information
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Regional Field Operations
Pre-Construction Conference May 2018
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Regional Field Operations
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NCDOT Regional Offices
Western Mobility and Safety Field Operations Region Central Mobility and Safety Field Operations Region Eastern Mobility and Safety Field Operations Region
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Regional Field Operations
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Regional Traffic Role
Field Investigations Funding
Mobility Funds $20 Million <$750K Spot Safety 12.1 Million <$400K
Systemic Projects
Guardrail End Units Signing Markings Median Barrier Fatal sites HSIP Sites
Countermeasures
Roundabouts Realignment Super elevation Traffic Signals Turn Lanes School Zones
Ordinances
Speed Limits Citizen Request
TIP Projects
Signal Recommendations No Parking, No Trucks, No U-turns, etc... HSIP Funds $40 Million $400K to $1M Public Officials Request Plan Review Directional crossovers AWS Work Zone Penalty $250 Signing Markings R/W, Maintenance Vulnerable User Signs Markings Division/City
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US 1 A (Main St)
Regional Field Operations
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Regional Field Operations
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Regional Field Operations
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US 1 A (Main St)
Regional Field Operations
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SR 1006 (Old Stage Rd)
Regional Field Operations
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Regional Field Operations
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Regional Field Operations
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SR 1006 at SR 1010
Regional Field Operations
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Regional Field Operations
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Regional Field Operations
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Regional Field Operations
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Before After
Spot Safety & Hazard Elimination
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Safety Planning
Pre-Construction Conference May 2018
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Safety Planning
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Safety Planning Group
Transportation Planning / STIP
(300+ per year)
Customer Service Requests
(400+ per year) Consultant Requests (TIAs / Project Related)
Fatal Crash Review Program
(900+ per year) Regional Traffic Engineers for Investigation Media Divisions Merger Team Divisions Project Development MPOs / RPOs / SPOT Office Citizens
TEAAS / Crash Data Management
(Shared with HSIP and TSIS) Large scale data linkages / Data issues 900+ TEAAS application users TEAAS application maintenance and enhancements Address Safety Issues for a corridor or special concern
Road Safety Reviews
Scoping Phase Fatal Notifications / Year-To-Date Metrics / Crash Analyses Alternative Analysis Project Support / Environmental Document Bridge Design Speeds Crash Analyses / Collision Diagrams / GIS Mapping / Ad-Hoc Queries Municipalities / MPOs / RPOs STI Support / Safety Benefit Factors Traffic Records Coordinating Committee
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Safety Planning
- Identify patterns of crashes the project should address
– Detailed Crash Analysis
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Project Scoping
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Safety Planning
- Identify patterns of crashes the project should address
– Detailed Crash Analysis – Mapping
- Helps to identify patterns
- Helps to communicate safety concerns
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Project Scoping
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Safety Planning
- Identify patterns of crashes the project should address
– Detailed Crash Analysis – Mapping
- Helps to identify patterns
- Helps to communicate safety concerns
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Project Scoping
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Safety Planning
- Compare the “Safety” of each Alternative
– How???
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Alternative Analysis
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Safety Planning
- Compare the “Safety” of each Alternative
– How??? – Predictive Analysis utilizing Safety Performance Functions
- Using crash, roadway, and traffic volume data to provide estimates of an existing or
proposed roadway’s expected safety performance
- Can be used to quantify the safety impacts of proposed transportation
improvements
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Alternative Analysis
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Safety Planning
- Safety Performance Functions
– Example: Base function for 2-lane rural roadway
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Alternative Analysis
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Safety Planning
- Methodology for Analyzing a Corridor Alternative
– Break corridor down into “like” segments
- Intersections, curves, tangents, etc.
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Alternative Analysis
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Safety Planning
- Methodology for Analyzing a Corridor Alternative
– Break corridor down into “like” segments – Analyze each segment individually
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Alternative Analysis
CMFs CMFs
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Safety Planning
- Methodology for Analyzing a Corridor Alternative
– Break corridor down into “like” segments – Analyze each segment individually – Incorporate existing crash history
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Alternative Analysis
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Safety Planning
- Methodology for Analyzing a Corridor Alternative
– Break corridor down into “like” segments – Analyze each segment individually – Incorporate existing crash history – Calculate predicted and expected crashes
- Predicted -> Based on calibrated safety performance function
- Expected -> Based on Empirical Bayes (EB) analysis
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Alternative Analysis
Crash History at Treatment Site Crash History at Large Pool Of Reference Sites (Described by SPF)
α 1 − α
Clue #1 Clue #2
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Safety Planning
- Methodology for Analyzing a Corridor Alternative
– Break corridor down into “like” segments – Analyze each segment individually – Incorporate existing crash history – Calculate predicted and expected crashes – Summarize results of each individual segment analyzed to get estimates for entire corridor
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Alternative Analysis
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Safety Planning
- Benefits of Alternative Analysis
– Quantifies expected safety for each alternative
- Allows safety to be part of the discussion when comparing all measurables (i.e.
wetlands impacted, relocations, etc.) for each alternative
– Often allows projects to move forward and not get mired down in subjective discussions
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Alternative Analysis
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Strategic Mobility Formula
Safety Planning
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