Keywords
Theme:
WIM, WIM, Weigh Station, Traffic, Weigh in motion, Automatic Traffic Recoder, WIM, Weigh in Motion
Place:
USA
Stratum:
ground
Temporal:
2006, 2007, 2008
Description
Abstract
The data included in the GIS Traffic Stations Version database have been assimilated from station description files provided by FHWA for Weigh-in-Motion (WIM), and Automatic Traffic Counters (ATR). Location referencing information was derived from the National Highway Planning Network version 4.0. and State offices of Transportation
The attributes on the point elements of the database have come from two primary sources, the Station Description Records and the National Highway Planning Network's Linear Referencing System. The attributes for these databases have been intentionally limited to location referencing attributes since the core station description attribute data are contained within the Station Description Tables (SDT).
There is a separate Station Description Table (SDT) for each of the different station types; WIM, and ATR. The attributes in the Station Description Table correspond with the Station Description Record found in Chapter 6 of the latest Traffic Monitoring Guide. The SDT contains the most recent stations available for each state and station type. This table was derived from files provided UTCTR by FHWA. The Station Description Table can be linked to the station shapefile via the STNNKEY field .
A single exception table containing records for those stations that could not be located is provided for WIM, and ATR stations. Generally, this table contains records where location descriptions were not clear enough to locate a station. It is hoped that FHWA will be able to contact the States for a more detailed description
Purpose
The GIS Traffic Stations database provides structural linkages between the National Highway Planning Network Weigh In Motion (WIM), and Automatic Traffic Count Stations (ATR)
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Status of the data
Complete
Data update frequency:
As needed
Time period for which the data is relevant
Date and time:
2008
Description:
publication date
Publication Information
Who created the data: Federal Highway Administration (FHWA), Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS)
Date and time:
2006
Publisher and place:
Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS), Washington, DC
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Data storage and access information
File name: wim
Type of data: vector digital data
Location of the data:
http://www.bts.gov/programs/geographic_information_services/
Data processing environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722
Accessing the data
Data format: ESRI Shapefile
Size of the data: 0.148 MB
Data transfer size: 0.148 MB
How to decompress the file: No compression applied. However, if using digital transfer online option, note access instructions.
Access instructions: NTAD is available for download at www.bts.gov/programs/geographic_information_services. The NTAD DVD can also be ordered from the online bookstore at www.bts.gov.
Available media: DVD
Constraints on accessing and using the data
Access constraints:
None
Use constraints:
Acknowledgment of Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS) National Transportation Atlas Databases (NTAD) 2008 would be appreciated in products derived from these data.
Details about this document
Contents last updated: 20080519
at time 08541600
Who completed this document
Geospatial Information Program
Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS)
mailing and physical address:
Washington, District of Columbia 20590
USA
(202) 366-DATA (voice)
answers@bts.gov
Standards used to create this document
Standard name: FGDC Content Standards for Digital Geospatial Metadata
Standard version: FGDC-STD-001-1998
Time convention used in this document: local time
Metadata profiles defining additonal information
ESRI Metadata Profile: http://www.esri.com/metadata/esriprof80.html
Horizontal coordinate system
Geographic coordinate system name: GCS_WGS_1984
Details
Geographic Coordinate System
Latitude Resolution: 0.000001
Longitude Resolution: 0.000001
Geographic Coordinate Units: Decimal degrees
Geodetic Model
Horizontal Datum Name: D_WGS_1984
Ellipsoid Name: WGS_1984
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257224
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Bounding coordinates
Horizontal
In decimal degrees
West:
-159.378753
East:
-65.760962
North:
68.665416
South:
18.065477
In projected or local coordinates
Left: -159.378753
Right: -65.760962
Top: 68.665416
Bottom: 18.065477
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Lineage
FGDC lineage
Process step 1
Process description: The station location description for each station type WIM, ATR, and Classification was used to manually adjust a station to the National Highway Planning Network (NHPN) v4.0. Any stations that could not be located on the NHPN were located on TIGER 99. Any stations that could not be located due to poor location descriptions are contained in the exception data table delivered with the GIS Traffic Stations.
Source used: UTCTR
Source used: FHWA
Source used: NHPN
Process date: 2001
Who did this process
David Jones
FHWA Office of Highway Policy Information
mailing and physical address:
202.366.5053 (voice)
202.366.7742 (fax)
david.jones@fhwa.dot.gov
Process step 2
Process description: Weigh Station collection began with FHWA delivering all new weigh station points ot RITA. Also acquried was the older University of Tennessee dataset to use as a comparison with new FHWA data. Analysis of data began by comparing the two datasets. All duplicate points were elimitnated from the new FHWA dataset. Once a final dataset was complete, a state-by-state analysis began. As each state's database was populated differently, analysis varied from state to state.
Process steps included indentifying county code per point. Determine broad location of road segment using LRS Id. Value could then be tied into the LRSKEY value on road segments.
If no LRS ID was provided, HPMS values were also used to determine location.
Finally, an exact point was determined by using the provided text description within the location field.
Once exact location was determined, edit session was begun and the point was manually created.
After all points were populated, the latitude and longitude fields were calculated using a script in an edit session.
The resulting dataset was then made into a shapefile.
Source used: RITA/BTS
Process date: 2006
Who did this process
Geospatial Information Program
Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS)
mailing and physical address:
202-366-DATA (voice)
202-366-3640 (fax)
answers@bts.gov
Process step 3
Process description: The attribute data for each WIM site consisted of 13 records. Each record represented a different vehicle classification. A volume count and average weight, where appropriate, was recorded for each vehicle classification for that site. These data were further categorized by State, and by year the data was submitted to the FHWA. The processing of the data was straight forward; summarize the 13 records for a given site to a single record and join this record to the existing spatial database of WIM sites. This was accomplished with the following process steps:
Step 1 - Where multiple stations existed for a single site, FHWA distilled these to a single station for that site (each station has 13 records representing a different vehicle classification). In some cases, not all stations for a site were captured by the FHWA before the data was delivered to RITA. In these cases RITA had to conduct special processing to distill these to a single station for the site.
Step 2 - In general, each site had 13 records. Each record represented a different classification of vehicle. Each record had a vehicle volume count for that classification and what percentage of the total volume it represented. Vehicle classes 1- 4 were passenger vehicles (i.e. cars), and classes 5 - 13 were trucks. This last group had average weight recorded when available. These 13 records were summarized to one record for the site. This processes consisted of separating truck and passenger vehicle volumes into different fields for the representative record of all vehicle classifications for that site. Truck and passenger volumes for the site were added together to obtain its total vehicle volume. All of the average gross vehicle weights were summarized. Total trucks were divided by total vehicle volume to obtain percent truck. This was added to the database. Truck volume was deleted from the database.
Step 4 - The processed attribute record for the WIM site was joined to the spatial data. Redundant fields were deleted.
Source used: RITA/BTS
Process date: 2006
Who did this process
Geospatial Information Program
Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS)
mailing and physical address:
202-366-DATA (voice)
202-366-3640 (fax)
answers@bts.gov
Sources
Source 1:
Weight Stations
(Weight Stations)
Media: computer program
Contribution: WIM/ATR site information, as reported by State DOTs to the FHWA, may consist of multiple data collecting stations for a single site, each identified by a unique identifier (ID).
Currentness of this source
Source 2:
WIM Attributes
(WIM Station Attribute)
Media: computer program
Contribution: WIM site information, as reported by State DOTs to the FHWA, may consist of multiple data collecting stations for a single site, each identified by a unique identifier (ID). WIM sites can be considered a complex of stations that make up the site. Multiple stations can be grouped together or associated to a single site through the ID. Common reasons for multiple stations for a single site are that each station represents a different direction or travel for that location, or multiple roads (sometimes each road will be a different Functional Classification) intersecting the site's location. Where multiple stations existed, for a given WIM site, FHWA summarized these to one station for the data it provide to RITA. This data was submitted to RITA, from the FHWA, in an excel spreadsheet.
Currentness of this source
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Spatial data quality
Horizontal positional accuracy
The elements of the GIS Traffic Stations have been conflated to the 1:100,000NHPN v4.0 data set which maintains a nominal accuracy of at least ±80 meters. Where no NHPN roads exist, the station was located using text description or teleatlas data.
Vertical positional accuracy
The elements of the GIS Traffic Stations have been conflated to the 1:100,000 NHPN v4.0 data set which maintains a nominal accuracy of at least ±80 meters. Where no NHPN roads exist, the station was located using text description or Teleatlas data.
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Spatial data description
Vector data information
ESRI description
wim
ESRI feature type: Simple
Geometry type: Point
Topology: FALSE
Feature count: 5553
Spatial Index: TRUE
Linear referencing: FALSE
SDTS description
Feature class: SDTS feature type, feature count
wim:
Entity point, 5553