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State Statistics
File Types
All of the selected
States maintain basic crash files, roadway inventory files, and traffic
files. In addition, individual States also collect other types of data.
Depending on the particular problem being studied, files from one or more
States may be used by the analyst. The following table indicates the files
that are available.
Crash - Contains basic accident, vehicle,
and occupant information on a case-by-case basis. Typical data include
type of accident, type of vehicle, sex and age of occupants, fixed-object
struck, accident severity, and weather conditions.
Roadway Inventory - Contains information
on roadway cross-section and the type of roadway. Data include the number
of lanes, lane width, shoulder width and type, median width, rural/urban
designation, and functional classification.
Traffic Volume - Contains annual average
daily traffic (AADT) data. Additional data on hourly volumes and percentage
of trucks is also available in selected States and/or locations.
Roadway Geometrics - Contains horizontal
curve and vertical grade information. Data include degree of curve, length
of curve, percent grade.
Vehicle Identification Number (VIN) -
Contains VIN data decoded using the VINDICATOR program. Data include
make and model, body style, body type, curb weight, and wheelbase.
Intersection - Contains information
on highway intersections. Data include traffic control type, intersection
type, signal phasing, and turn lanes.
Interchange/Ramp - Contains information
on highway interchanges. Data include interchange type and ramp characteristics.
Guardrail/Barrier - Contains
an inventory of guardrail. Data include guardrail type, post type, rail
height, and terminal type.
Data Quantity
The HSIS contains only police-reported accident data on the State-maintained highway system. The size
of the State-maintained system depends on the policies of the State and is not necessarily proportional
to the size of the State. Data for the original five HSIS States are available from 1985, while data for
the three new HSIS States are available from 1991, and data for Ohio is available from 1997. The following
table provides an indication of the quantity of data available.
|
First
Year
Available |
Average
Accidents/Year |
Roadway
Mileage |
| California |
1991 |
160,000 |
15,300 |
| Illinois |
1985 |
120,000 |
15,400 |
| Maine |
1985 |
39,000 |
19,800 |
| Michigan |
1985 |
145,000 |
9,500 |
| Minnesota |
1985 |
77,000 |
51,000 |
| North
Carolina |
1991 |
97,000 |
34,200 |
| Ohio |
1997 |
75,000 |
16,800 |
| Utah |
1985 |
46,000 |
9,300 |
| Washington |
1993 |
38,000 |
7,200 |
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