1. School of Civil Engineering
Highway Traffic and Safety Analyses
Lecture 16: Road Safety Concepts
Purdue University
School of Civil Engineering
West Lafayette

2. Road Safety and Its Measurement
What is road safety?
Road safety crosses multiple areas
Stakeholders of highway safety
Present issues
Safety Management System
Objective, perceived, and nominal safety
Measures of safety

3. Road Safety When is a road considered safe?
Basic facts about road safety

4. Hadden’s Matrix Road safety crosses multiple areas
Travelers
Vehicle
Road +
Environment
Pre-Crash Crash Post-Crash
Attitudes
Driver Skills
Alcohol/Drug Use
Vision
Education
Safety Belts Use
Air Bags
Side Impact Protection
Traveler’s Age
Traveler’s Health
First Aid Training
Safety Equipment
Vehicle Design
Vehicle Size
Vehicle Weight
Automatic Seatbelts
Fuel System Integrity
Road Design
Weather Conditions
Road Operation
Road Maintenance
Lighting
Delineation
Roadside Hazards
Fixed Objects
EMS Response
Hospitals
Availability of Med. Services
Matrix developed by William Hadden, Insurance Institute for Highway Safety

5. Stakeholders of Road Safety
Legislature (funding, safety law and regulations)
Government (overseeing)
Road administration (road safety management)
Bureau of motor vehicles (safety through proper licensing)
Police (crash data, enforcement)
Public research agencies (knowledge enhancement)
Auto industry (observance of safety regulations, competition)
Highway industry (safe road construction)
Freight industry (safe trucks operation)
Railroad industry (safe railway construction and operation)
Insurance industry (reduce crash costs)
Emergency medical services (reduce crash consequences)
Private consultants (research, analysis, service)
Citizens coalitions (lobbying for safety improvements)

6. Organizations Involved in Road Safety
United States Department of Transportation American Association of State Highway and Transportation Officials (AASHTO)
National Association of Governors Highway Safety Representatives (NAGSHR)
National Transportation Safety Board (NTSB)
Mothers Against Drunk Driving (MADD)
Insurance Institute for Highway Safety (IIHS)
American Automobile Association (AAA) Traffic Safety Foundation
American Association of Motor Vehicle Administrators (AAMVA)
American Association of Retired Persons (AARP)
National Safety Council (NSC)
Bicycle Federation of America
American Trucking Association (ATA)
Transportation Research Board (TRB)
American Road and Transportation Builders Association (ARTBA)
Roadway Safety Federation (RSF)
American Traffic Safety Services Association (ATSSA)

7. Safety Emphases Special Users - pedestrians and bicyclists
Drivers - curbing aggressive driving, reducing impaired driving, keeping drivers alert, increasing driver safety awareness, seat belt usage, aging drivers
Special Users - pedestrians and bicyclists
Vehicles - motorcycle and commercial truck safety, vehicle safety enhancements (antilock brake systems)
Highways - vehicle-train crashes, highway intersection design and operation, head-on and across-median crashes, and work zones
Emergency Medical Services - increase survivability of crash victims
Management - gathering and analyzing crash data

8. Safety Emphases Highways Management Reducing Vehicle-Train Crashes
Keeping Vehicles on the Roadway
Minimizing the Consequences of Leaving the Road
Improving the Design and Operation of Highway Intersections
Reducing Head-on and Across-median Crashes
Designing Safer Work Zones
Management
Improving Information and Decision Support Systems
Creating More Effective Processes and Safety Management Systems

9. Safety Management System
1991 ISTEA required SMS from state DOTs
1997 TEA-21 - Transportation Equity Act for the 21st Century doesn’t require SMS
SMS developed by some states anyway
Florida
North Carolina

10. Safety Management System Cycle
Safety-related Decision Making
Safety Projects Implementation
Safety Data Acquisition and Management

11. Safety Management System Decision-making Process
Identify highway hazard
Determine causes
Determine countermeasures
Develop safety projects
Select projects for implementation
Evaluate projects effectiveness

12. Objective, perceived, and nominal safety
Objective safety – measured with crashes
Perceived safety – felt by motorists
Nominal safety – measured with compliance to design and operational safety standards

13. Measures of Safety Expected crash frequencies (crash/year)
Expected crash rates (crash/unit exposure)
Example unit exposures (used by Fatality Analysis Reporting System)
100,000,000 vehicle-miles traveled (VMT)
100,000 registered vehicles
100,000 licensed drivers

14. Measures of Safety http://www.nhtsa.dot.gov/people/ncsa

15. Measures of Safety http://www.nhtsa.dot.gov/people/ncsa