Introduction to Transportation Safety

1
Introduction to Transportation Safety

• CRP 445/545
• September 2007

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Outline for Today

• The scale of the transportation safety issue
• Compared to what? Accidental death statistics
• Exposure a key concept for understanding
  transportation safety
  
• Transportation safety trends over time
• A very brief history of transportation safety
  policies
  
• The three rings of safety
• Operators (human factors)
• Guideways (roads, airways and airports,
  waterways, railroads) and the Environment
  (weather and other natural phenomena)
  
• Vehicles (cars, trucks, buses, aircraft, trains,
  ships)
  
• Analyzing safety key data sources and methods
• The quasi-random nature of fatal transportation
  accidents
  
• Whos involved in making transportation safer?

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Outcomes The Scale of the Transportation Safety
Issue

• Transportation accidents account for more deaths
  than all natural disasters combined
  
• Your odds of dying in a transportation accident
  in any given year are about 1 in 6000
  
• Your odds of dying in a transportation accident
  in your lifetime are about 1 in 80, assuming a 75
  year lifespan
  
• Your odds of being injured in a transportation
  accident are better than 1 in 1000 in any given
  year
  

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Long-Term Safety Trend

• These statistics are a bit old
• But guess what? They havent changed that much in
  recent years
  
• We have hit a plateau in transportation safety
• Fatality rate is now pretty constant
• As travel goes up, fatalities will start to rise
  again

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The Fatalities Plateau
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Fatality Rate vs. Injury Rate
Why the difference in trends? Any thoughts?
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Over Half of Accidental Deaths Involve
Transportation
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Transportation is the Dominant Cause of
Accidental Deaths
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Transportation Deaths Compared to Other Causes of
Death from Injuries
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Outcomes The Cost of the Transportation Safety
Issue

• Improving transportation safety has major
  economic implications
  
• Motor vehicle crashes are the leading cause of
  death in the US for persons aged 5 through 27
  
• Huge loss in future economic production
• The direct cost of crashes to the economy is
  about 150 - 200 billion/year
  
• (Estimate is a bit old, should be higher now)
• Lost productivity, health care, property losses,
  insurance
  
• About 1 ½ to 2 of the entire 1 trillion US
  economy represents losses from transportation
  accidents
  
• About 40,000 fatalities, 5.2 million other
  injuries, and 27 million damaged vehicles
  

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A Brief History of Transportation Safety Policies

• There was surprisingly little interest in US
  transportation safety issues until the 1960s.
  
• Most effort before 1960 went into improving the
  safety of vehicles, e.g. better tires and brakes
  
• At that point in time many policies aimed at
  improving safety were initiated
  
• Investigations of major airline crashes (NTSB)
• Motor vehicle safety standards (e.g. seat belts
  and mandatory crash testing) and tire grading
  standards (NHTSA)
  
• Major reviews/research into highway geometric
  design
  
• Tougher standards for commercial trucks and
  drivers (USDOT)
  
• Since the 1960s safety has improved tremendously
  when increased exposure is taken into account
  

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What Is Exposure?

• In order to make reasonable comparisons of
  relative safety among trips and modes,
  adjustments for exposure are necessary
  
• Exposure is usually a function of miles traveled
  or trips made
  
• Passenger-miles, vehicle-miles, passenger trips,
  flights, etc.
  
• Fatality rate fatalities / exposure
• Risk f (exposure, fatality or crash rate)
• How much exposure to transportation risk do you
  have in a month?

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Example Urban Transportation Fatality Rates for a
Year
Rates for modes with small exposure (e.g. light
rail) will tend to be very volatile. One event c
an dramatically change the fatality rate.
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Selected Intercity Transportation Fatality Rates
for a Year
Rates for modes with small exposure (e.g.
intercity rail and commuter airlines) will tend
to be very volatile. Why do you think the number
for rail is so high? Why is the number for
commuter airline so low?
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A Fundamental Shift In Automobile Transportation
1969-1995
In Iowa, there are now more vehicles than driver
s
NTPS is the National Personal Transportation
Survey
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Airline Activity Increased Very Rapidly Much
More Exposure
Activity declined after 9/11, but recovering ba
ck to trend
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Airline Fatality Rates Fluctuate But Have Trended
Downward
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Exposure Has Dramatically Increased Since The
1920sDeaths Adjusted For Exposure Are
Dramatically Lower
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Highway Death Rates Adjusted for Exposure Have
Been Were Almost In HalfAfter 1965 Why?
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Crash Rates Exhibit Considerable Variation

• Males are twice as likely to die in a
  transportation accident than females
  
• A product of higher exposure AND a higher rate of
  involvement in crashes
  
• Want to comment on this?
• The risk of dying in a transportation accident
  varies tremendously from place to place
  
• Six times as high in Wyoming (39 deaths per
  100,000 persons) as in Massachusetts (7)
  
• Iowa (17), Illinois (12), Minnesota (13),
  Missouri (20), Nebraska (18), South Dakota (20),
  Wisconsin (14)
  
• Why do you think there is a large variation?

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Men Travel More Person-Miles Than Women More
Exposure
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Possible Sources of Variation?
Iowa
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Crash Rates Exhibit Considerable Variation

• Crash rates can vary considerably from year to
  year, especially on individual system links
  
• In Iowa, nearly half of all crashes occur during
  the winter months in inclement weather as drivers
  fail to adapt to poor road surface conditions
  
• Crashes and crash rates vary by time of the year
  (due to weather) and time of day (due to
  visibility and presence/absence of drunk
  drivers)
• Many fatal crashes occur at night and on weekends

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What Causes Highway Crashes?The Haddon Diagram

• Over 1/3 of crashes involve
• more than one primary
• cause
• Driver error or impairment is by far the greatest
  cause of
  
• crashes
• Driver/roadway/environment
• interactions are very significant
• in generating crashes
• Vehicle problems
• are the least common cause of crashes

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An Indication of the Importance of Human
FactorsDriver Risk Varies Dramatically By Age
Risk adjusted for exposure e.g. miles driven.
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What Causes Accidents For Other Modes? Airlines

• Causation statistics for other modes (e.g.
  railroads, maritime transport, and aviation) are
  similar
  
• For instance, most major airline crashes have
  been determined by NTSB to result from pilot
  error or other human factors (maintenance or
  design errors), weather conditions, or a
  combination of the two
• Controlled flight into terrain (CFIT)
• Loss of control in flight
• Mid-air collision
• Crash on landing

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Human Factors Cause Most Airline Crashes and
Fatalities
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Three Types of Safety Strategies

• Crash prevention (before the crash)
• Crash injury and fatality mitigation (during the
  crash)
  
• Improving emergency response and medicine (after
  the crash)

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Some Crash Prevention Strategies

• Commercial driver testing and licensing
• Drunk driving limits and enforcement
• Speed limits and speed limit enforcement
• Standardization of traffic control devices
• Improvement of roadway geometric designs
• Managing direct access to land from arterial
  roads
  
• Aircraft safety regulation and inspection
• Post-crash investigations and analysis of crash
  data (e.g. IHSDS in Iowa, FARS, and NTSB at
  Federal level)
  
• Camera enforcement of speed and red light
  running
  
• Road condition and weather information (e.g.
  511)
  

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Some Mitigation Strategies Reduce The
Consequences of Crashes

• Wider roadway clear zones
• Ditch slope standards
• Improved roadway medians
• Crash testing of vehicles and roadside hardware
• Automobile safety feature requirements (e.g. seat
  belts, air bags, tire grading, stability
  control)
  
• Flammability standards for materials used in
  aircraft cabins and inside automobiles
  
• Improved guard rails and breakaway posts

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Emergency Response Strategies

• Improved crash fire and rescue capabilities at
  airports
  
• Training and certification of emergency medical
  technicians
  
• Enhanced 911 systems (E-911)
• Video surveillance of high crash locations
• Pre-positioning of emergency response vehicles
• Mayday systems on motor vehicles

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Many Actors Are Involved in Transportation Safety

• Federal agencies US DOT (FHWA, NHTSA, NTSB)
• State agencies (DPS, DOT)
• Local agencies (roads and streets, police)
• Private sector (insurance companies, trade
  organizations like Insurance Institute for
  Highway Safety, motor vehicle manufacturers, K-12
  schools, trucking companies, aircraft
  manufacturers, airlines)

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Primary Safety Data Sources

• FARS
• Police report data
• Iowa example ALAS
• NTSB investigations

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Fatality Analysis Reporting System (FARS)

• Compiled by the US Department of Transportation,
  National Highway Traffic Safety Administration
  (NHTSA)
  
• Contains about 37,000 records per year of fatal
  highway crashes in all 50 states
  
• Can be queried on-line at http//www-fars.nhtsa.d
  ot.gov/
  
• Useful for understanding causes of fatal crashes,
  however not a geospatial database

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Sample National Statistics From FARS
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Police Accident Report Databases Iowas Crash
Database

• Iowa is one of several states that has
  computerized its police crash report data
  
• About 70,000 records per year are available in
  either Microsoft Access database or ESRI ArcView
  Geographic Information System (GIS) format
  
• A geospatial databasecan be used to develop
  complex queries and maps

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Mapping Ice and Snow-Related Crashes With GIS
These maps helped identify a roadway icing probl
em on I-380 in Cedar Rapids
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NTSB Investigation Results

• The National Transportation Safety Board (NTSB)
  is an independent Federal agency that
  investigates major, fatal transportation
  accidents with interdisciplinary teams
• Aviation, maritime, motor carrier, intercity bus,
  school bus, and pipeline (concentrates heavily on
  aviation)
  
• Examples TWA flight 800 explosion, ValueJet
  Everglades crash, Alaska Air crash, JFK Jr., USS
  Greenville/Ehime Maru sinking, Payne Stewart
  crash, major railroad crashes (hazmat, school
  bus)
• Investigation results and recommendations are
  released to the public
  
• Companies and agencies generally comply with
  recommendations
  

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Fatal Crashes Are Fairly Random Events

• They often have multiple or unusual causes
• For instance
• A driver with a heart condition is driving a
  large commercial vehicle with poor brakes during
  morning rush hour, has a heart attack and crosses
  a grass median into opposing traffic
• Two experienced commercial pilots fail to look up
  a navigation code in a long list, guess at the
  code, enter the wrong code into a computer and
  the autopilot flies the plane into a mountainside
  at night (American Airlines crash in Columbia,
  South America)

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A Fatal Crash What Was the Cause?
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Injury Accidents Show Spatial Patterns, Fatal
Crashes Usually Do Not (They Are Rare And To Some
Extent Random Events)
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Implications

• One implication of this
• Chasing fatalities can be an expensive and
  futile activity
  
• Next years fatal crash location will probably be
  different than this years
  
• Highway safety engineers will instead tend to
  identify high crash rate locations based on
  serious injury crashes rather than fatalities
  only
• Fatal crashes may be counted as injury crashes
• More data means more reliability

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Next Three Classes

• Improving vehicle safety focus on motor
  vehicles
  
• Discussion what features could you
  change/add/eliminate to make motor vehicles
  safer?
  
• Improving the safety of guideways focus on
  highways, airways, and weather
  
• What features of guideways could be changed to
  improve safety?
  
• Improving operator safety focus on drivers,
  commercial vehicle operators, and pilots
  
• What are some key human factors issues and how
  can they be addressed?
  
• Safety data and analysis tools
• Discussion your short papers on safety

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Discussion Transportation Safety

• Small group discussion
• Have you been involved in a traffic crash where
  there were injuries?
  
• What were the causes?
• What can you personally do to make transportation
  safer for your self, your family, and your
  friends?
  
• Think exposure
• Vehicle considerations
• Guideway and weather considerations
• Driver behavior