using nhts data as a measure of exposure data meg sweeney* lee giesbrecht jonaki bose bureau of...
DESCRIPTION
Number of Fatal, Single-Vehicle Crashes per 100,000 Registered Vehicles, 2001 Sources: Subramanian, R. (2004). Analysis of crashes involving 15-passenger vans (NHTSA Technical Report DOT HS ). Washington, DC; Mathematical Analysis Division, National Center for Statistics and Analysis, National Highway Traffic Safety Administration. NCSA, NHTSA, FARS (Final), 2002 (ARF) Files and R.L. Polk and Company NVPP Registration DataTRANSCRIPT
Using NHTS Data as a Measure of Exposure Data
Meg Sweeney*Lee Giesbrecht
Jonaki BoseBureau of Transportation Statistics
This work was completed while Meg Sweeney was employed at the Bureau of Transportation Statistics
Accident Rate
Accident MeasureNumber of Fatal AccidentsNumber of Large Truck AccidentsNumber of Injuries
Exposure MeasureNumber of Registered Vehicles Number of Licensed Drivers
Number of Fatal, Single-Vehicle Crashes per 100,000 Registered Vehicles, 2001
02468
10121416
PassengerCars
SUVs PickupTrucks
15-Passenger
Vans
Other Vans
Vehicle Type
Rat
e of
cra
shes
per
100
K
regi
ster
ed v
ehic
les
Sources: Subramanian, R. (2004). Analysis of crashes involving 15-passenger vans (NHTSA Technical Report DOT HS 809 735.). Washington, DC; Mathematical Analysis Division, National Center for Statistics and Analysis, National Highway Traffic Safety Administration.NCSA, NHTSA, FARS 1990-2002 (Final), 2002 (ARF) Files and R.L. Polk and Company NVPP Registration Data
Vehicle Involvement Rate in Fatal Crashes per 100,000 Registered 15-Passenger Vans
in the U.S., 1990-2001
010203040506070
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Year
Vehi
cle
Invo
lvem
ent R
ate
per
100K
Reg
iste
red
Vans
Sources: Subramanian, R. (2004). Analysis of crashes involving 15-passenger vans (NHTSA Technical Report DOT HS 809 735.). Washington, DC; Mathematical Analysis Division, National Center for Statistics and Analysis, National Highway Traffic Safety Administration.R.L. Polk & Co., National Vehicle Population Profile (NVPP), 1990-2002 and NCSA, NHTSA, FARS 1990-2002 (Final), 2002 (ARF) Data.
Need for Additional Exposure Data
• Time of Day• Driver Age
• National Household Travel Survey
National Household Travel Survey
• Computer assisted telephone interview• Collected April 2001 to May 2002• Includes demographic information on
households, people, and vehicles• Detailed information on daily and long
distance travel
NHTS Exposure Measure
• Estimated number of drivers on the road during a given hour
• Daily travel data• Weighted estimates
Drivers on the road (NHTS)
0100000002000000030000000400000005000000060000000
Time of day
Num
ber
of d
rive
rs o
n th
e ro
adw
ay
Accident Rate
Number of drivers involved in fatal (FARS) or fatal, injury, or property damage (GES) accidents in a given hour
Estimated number of drivers on the roadway during that hour
Fatality Analysis Reporting System (FARS)
• Census of all highway accidents • Death of an occupant of a vehicle or
nonmotorist within 30 days of crash• Motor vehicle traveling on trafficway
customarily open to public• Information on the crash, vehicles and
people involved
Fatal accident involvement (FARS)
0500
100015002000250030003500400045005000
Time of day
Num
ber
of d
rive
rs in
volv
ed in
ac
cide
nts
General Estimates System (GES)
• Nationally representative probability sample selected from all-police reported crashes
• To be eligible for selection:– Completed PAR– Involve at least one motor vehicle traveling on
trafficway – Result in property damage, injury, or death
• Information on crash, drivers, and vehicles• Weighted data
Injury, Property, and Fatal Accident Involvement (GES)
0200000400000600000800000
100000012000001400000
Time of day
Num
ber
of d
rive
rs in
volv
ed in
ac
cide
nts
FARS and GES Analysis
• Drivers of passenger cars and motorcycles • Aged 15 years and older • April 2001 to May 2002• Accident types:
– Total accidents– Fatigue-related accidents– Failure to yield accidents– Alcohol-related accidents
Fatal Accidents
01000
20003000
40005000
0000
-0059
0200
-0259
0400
-0459
0600
-0659
0800
-0859
1000
-1059
1200
-1259
1400
-1459
1600
-1659
1800
-1859
2000
-2059
2200
-2259
Time of day
Driv
ers
invo
lved
in
fata
l acc
iden
ts
00.0005
0.0010.0015
0.0020.0025
Driv
ers
invo
lved
in
fata
l acc
iden
ts/d
river
s on
the
road
Fatal accidents Fatal accident rate
Fatal Fatigue-related Accidents
020406080
100120140160180
Time of day
Driv
ers
invo
lved
in
fata
l fat
igue
acc
iden
ts
00.000050.00010.000150.00020.000250.00030.00035
Driv
ers
invo
lved
in
fata
l fat
igue
ac
cide
nts/
driv
ers
on
the
road
Fatigue accidents Fatigue accident rate
Fatal Alcohol-related Accidents
0200400600800
1000120014001600
0000
-0059
0200
-0259
0400
-0459
0600
-0659
0800
-0859
1000
-1059
1200
-1259
1400
-1459
1600
-1659
1800
-1859
2000
-2059
2200
-2259
Time of day
Driv
ers
invo
lved
in
fata
l fat
igue
acc
iden
ts
00.00020.00040.00060.00080.0010.0012
Driv
ers
invo
lved
in
fata
l fat
igue
ac
cide
nts/
driv
ers
on
the
road
Alcohol accidents Alcohol accident rate
Fatal Failure to Yield Accidents
0100
200300
400500
0000
-0059
0200
-0259
0400
-0459
0600
-0659
0800
-0859
1000
-1059
1200
-1259
1400
-1459
1600
-1659
1800
-1859
2000
-2059
2200
-2259
Time of day
Driv
ers
invo
lved
in
fata
l fat
igue
acc
iden
ts
00.000010.000020.000030.000040.000050.000060.00007
Driv
ers
invo
lved
in
fata
l fat
igue
ac
cide
nts/
driv
ers
on
the
road
Failure to yield accidents Failure to yield accident rate
Accident Involvement (GES)
0200000400000600000800000
100000012000001400000
Time of day
Num
ber
of d
rive
rs
invo
lved
in a
ccid
ents
00.020.040.060.080.10.12
Num
ber
of d
rive
rs
invo
lved
in
acci
dent
s/N
umbe
r of
dr
iver
s on
the
road
GES accidents GES Accident rate
Failure to Yield Accident Involvement (GES)
010000200003000040000500006000070000
Time of day
Num
ber
of d
rive
rs
invo
lved
in a
ccid
ents
00.00020.00040.00060.00080.0010.00120.00140.0016
Num
ber
of d
rive
rs
invo
lved
in
acci
dent
s/N
umbe
r of
dr
iver
s on
the
road
Failure to yield Accident rate
Accident Rate Comparison (FARS)
00.00020.00040.00060.00080.001
0.0012
Time of day
Num
ber o
f driv
ers
invo
lved
in
acc
iden
ts/N
umbe
r of
driv
ers
on th
e ro
ad
Fatigue accident rate (FARS) Alcohol accident rate (FARS)
Fatigue-related Accident Rates
00.0010.0020.0030.0040.0050.006
0000
-0059
0300
-0359
0600
-0659
0900
-0959
1200
-1259
1500
-1559
1800
-1859
2100
-2159
Time of day
Num
ber o
f driv
ers
invo
lved
in
acci
dent
s/N
umbe
r of
driv
ers
on th
e ro
ad
00.000050.00010.000150.00020.000250.00030.00035
Num
ber o
f driv
ers
invo
lved
in
acci
dent
s/N
umbe
r of
driv
ers
on th
e ro
ad
Fatigue accident rate (GES) Fatigue accident rate (FARS)
Alcohol-related Accident Rates
00.00020.00040.00060.00080.001
0.0012
0000
-005
902
00-0
259
0400
-045
906
00-0
659
0800
-085
910
00-1
059
1200
-125
914
00-1
459
1600
-165
918
00-1
859
2000
-205
922
00-2
259Num
ber o
f driv
ers
invo
lved
in
acc
iden
ts/N
umbe
r of
driv
ers
on ro
ad
00.0050.010.0150.020.0250.03
Num
ber o
f driv
ers
invo
lved
in
acc
iden
ts/N
umbe
r of
driv
ers
on th
e ro
ad
Alcohol accident rate (FARS) Alcohol accident rate (GES)
Failure to yield Accident Rates
00.00020.00040.00060.00080.001
0.00120.00140.0016
0000
-0059
0300
-0359
0600
-0659
0900
-0959
1200
-1259
1500
-1559
1800
-1859
2100
-2159
Time of day
Num
ber o
f driv
ers
invo
lved
in
acci
dent
s/N
umbe
r of
driv
ers
on th
e ro
ad
00.000010.000020.000030.000040.000050.000060.00007
Num
ber o
f driv
ers
invo
lved
in
acci
dent
s/N
umbe
r of
driv
ers
on th
e ro
ad
Failure to yield accident rate (GES)Failure to yield accident rate (FARS)
Exposure by time of day and Age
02000000400000060000008000000
10000000120000001400000016000000
Time of day
Driv
ers
on th
e ro
ad
15-1819-2425-3435-4445-5455-6465 and older
Fatal Accidents by Time of Day and Age
02468
1012
Time of day
Perc
ent o
f fat
al a
ccid
ents
15-1819-2425-3435-4445-5455-6465+
Rate of accident involvement by age and time of day
00.0010.0020.0030.0040.0050.0060.007
15-1819-2425-3435-4445-5455-6465+
Fatal Fatigue Accidents by Time of Day and Age
0102030405060
0000
-0059
0200
-0259
0400
-0459
0600
-0659
0800
-0859
1000
-1059
1200
-1259
1400
-1459
1600
-1659
1800
-1859
2000
-2059
2200
-2259
Time of day
Num
ber o
f driv
ers
invo
lved
in
fata
l fat
igue
acc
iden
ts
15-1819-2425-3435-44 45-5455-6465+
Rate of fatigue accidents by age and time of day
00.00010.00020.00030.00040.00050.0006
15-1819-2425-3435-4445-5455-6465+
Summary• Calculated rates using NHTS data as a measure of
exposure• The patterns of the accident rates show a peak in
the early morning hours • Rates reveal different patterns from number of
drivers involved in accidents• Patterns of rates for FARS and GES data may not
be the same• Exposure information shows differences by age• Refinement of the exposure measure