WK 3 91213 LEC 5 Databases

9/17/2013
Dr. Khalil
ME 8020 Crashworthiness and Occupant
Protection in Transportation Systems -I
Week 3 Lecture 5
Crash Data
(NASS, GES, CDS, SCI, FARS)
September 12, 2013
1
History of Crash Investigations
9/17/2013
Dr. Khalil
NHTSA was created in 1970 following the Highway
Safety and Motor Vehicle safety acts of 1966
(www.nhtsa.dot.gov)
It deals with traffic safety issues:
Safety standards
Research on biomechanics of injury
Research on vehicle crashworthiness
Vehicle safety ratings
Consumers complaints
Crash investigations
Statistics (NCSA)
Etc.
2
History of Crash Investigations
9/17/2013
Dr. Khalil
Cornell University - Crash Injury Research (CIR) Project
Hugh DeHaven - pioneered aircraft crash investigation -1940s
Automobile CIR began in 1953 at Cornell Aeronautical Labs
(now Cal span?)
U of M - Huelke/Gikas began investigating fatal crashes 1960s
Identified design features contributing to injuries
Evolved over time to in-depth studies
Multidisciplinary accident investigation teams
Approach based on Haddon Matrix
Investigators from many disciplines
Formalized in-depth investigations
3
History of Crash Investigations (NCSS)
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Dr. Khalil
NCSS - National Crash Severity Study
Pilot program 1977 - 1979
Designed by UMTRI
Statistically representative crash investigation data base
Detailed info on cars & occupants
Towed away vehicles
7 geographical areas
Stratified sampling plan
Statistical weighting
4
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Dr. Khalil
Crash Investigation Databases
NHTSA designed & developed the following data
systems to provide overall measure of highway
safety:
FARS
NASS/GES
NASS/CDS
NASS/SCI
CIREN
NHTSAs Website - publicly available data files
5
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Dr. Khalil
NASS - National Automotive Sampling System
Based on NCSS
Operating since 1979
Randomly select representative cases from hundreds of
thousands of Police Accident Reports (PARS)
Randomly select areas of U.S. counties and cities
www.nhtsa.dot.gov/departments/nrd30/ncsa/NASS.html
Crash Investigation Databases (NASS)
6
9/17/2013
Dr. Khalil
NASS: two major data bases
- General Estimate System (GES)
Focus on overall cash trends, big picture
- Crashworthiness Data System (CDS)
Focus on injuries in passenger vehicles to
propose improvements
&
- Specific Crash Investigations system (SCI)
Focus on specific highway safety issues, as may
be mandated by congress or some research
issue concerning new technology
7
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Dr. Khalil
8
General Estimate System (NASS/GES)
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Dr. Khalil
Started in 1988
Collects data from large sample of police reported
crashes annually
Crashes of all severities
Nationally representative sample
Doesnt investigate crashes
Only basic PARS data entered
Annual report (NASS/GES) published
Tracks trends and overall crash picture
9
Crashworthiness Data System (NASS/CDS)
9/17/2013
Dr. Khalil
Collects detailed data from thousands of police
reported towed, passenger vehicle crashes per year
Focus on injuries to recommend design improvements
Uses trained, professional investigation teams
Information collected include: exterior damage,
interior damage, injuries, scene investigation,
environmental conditions, etc.
Detailed, in-depth information
Vehicle damage
VIN
Crash delta V from CRASH 3
Injuries and occupant details
10
Specific Crash Investigations (SCI)
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Dr. Khalil
Conducts investigations to acquire detailed
information on highly visible traffic crashes
Examine the impact of new safety technology such as
air bags, alternate fuel systems
Investigate airbag inflation-related deaths and serious
injuries
Investigate alleged defects
Helps the agency in formulating response to its
internal customers (safety standards, R&D)
Develops new technology to improve traffic safety
11
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Dr. Khalil
CIREN
Created in 1996 by NHTSA
ER-based investigations of crash injuries at 8 level 1 trauma
centers
Multi-disciplinary teams of clinicians and engineers from
industry, government, and academia
The file includes data from severe motor vehicle crashes,
including crash reconstruction and injury description
Crash Investigation Databases: CIREN
(Crash Injury Research & Engineering Network)
12
CIREN Centers Locations
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Dr. Khalil
13
Fatality Analysis Reporting System FARS
9/17/2013
Dr. Khalil
It monitors all fatal crashes on public roads in the U.S.
and Puerto Rico
STARTED IN 1975
FARS data files on NHTSA website since 1996
(www.fars.nhtsa.dot.gov/)
It must involve a death of occupant and/or pedestrian
Based on police collected data
Each case file contains >100 entries, characterizing the
vehicle, the occupants, etc.
14
Fatality Analysis Reporting System FARS
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Dr. Khalil
Four forms:
Accident form: information on date, time, location,
number of vehicles involved, number of people
involved, other information,
Vehicle form: type, impact point, .
Driver form: license, alcohol, .
Occupants form: age, gender, injuries, .
15
Police-Collected Data
9/17/2013
Dr. Khalil
All Injury-producing collisions (passenger cars, trucks,
motorcycles, pedestrians) on public roads in a given
state
May not report off-road or private-property damage
Fatal crashes investigated most thoroughly
Location
Environment
Vehicles
Injured occupants
Circumstances
Narrative & diagram of accident
16
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Dr. Khalil
States collect & computerize some records:
Driver
Traffic engineering
Selective enforcement
Problem identification
Narrative & diagrams not stored
17
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Dr. Khalil
Injury Coding:
K - Fatal
A - Incapacitating injury
B Non incapacitating injury
C - Minor injury
O - Not injured
Vehicle Damage:
Area of damage indicated on chart
Damage coding (some states)
0 -7 Scale
Officer compares to pictures
18
9/17/2013
Dr. Khalil
Problems:
Vehicle identification may be difficult
Level of detail poor
Lack of specific injury identification
Crude estimate of crash severity
Some data can be suspect
No standard format
19
In-Depth Investigations
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Dr. Khalil
Trained investigators
Sponsors include:
Insurance companies
Auto manufacturers
Government agencies
On-scene investigation
(sometimes)
20
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Dr. Khalil
21
In-Depth Investigations
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Dr. Khalil
Detailed description of vehicle damage
Hospital & autopsy reports
Specific injuries (AIS) and contacts coded
Expensive, thus small sample
22
Abbreviated Injury Scale (AIS)
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Dr. Khalil
0 no injury
1 minor
2 moderate
3 serious
4 severe
5 critical
6 fatal
7 (or 9) injured, severity unknown
23
Methods of Analysis
Estimating Crash Severity: V
9/17/2013
Dr. Khalil
Velocity change (V) based on:
Pre-crash speeds
Skid marks
Vehicle trajectories from point of impact to final
position
Crash damage measurement
Computer programs - CRASH & SMAC
Conservation of momentum & energy
Requires representative vehicle stiffness
24
Methods of Analysis
HARM
9/17/2013
Dr. Khalil
(Mallieris, 1980s)
Measure of cost to society
Allows analysis of major and minor Injuries
Used for cost/effectiveness studies
25
Overview of Statistical Studies
9/17/2013
Dr. Khalil
NHTSAs National Center for Statistics and Analysis
(NCSA) provides:
From FARS & GES - General Trends:
Fatality and injury rates
Age and gender
Alcohol
Vehicle Type (passenger, truck, motorcycle)
Speed limit - rural v urban roads
Time of day - weekday vs. weekend
From NASS/CDS
Vehicle crash data
Occupant injury data
26

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9/17/2013

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