Washington State Department of Transportation
The information in this file is for software developers. If you are looking for traffic information please start your search at http://www.wsdot.wa.gov .
Traffic Data Archive Folder Structure
The URL http://data.wsdot.wa.gov/traffic holds WSDOT traffic data for access by third parties. Generally, you will need an agreement to use this data. You can obtain an agreement by contacting:
Data Use Agreement Contact:
Jeremy Bertrand
360-705-7872
BertraJ@wsdot.wa.gov
The folder structure is fairly simple if you know the acronyms below:
EA – Eastern region
HQ – Headquarters
NC – North Central region
NW – Northwest region
OR – Olympic Region
SC- South Central region
SW – South West region
From the root folder (data.wsdot.wa.gov/traffic) there are six region subfolders, a Headquarter folder and a folder named WebFlow.
/Documentation Descriptions of the folders and files
/WebFlow Data for WSDOT planned new version of
WebFlow
/EA Data from the Eastern Region
/HQ Data from Headquarters
/NC Data from North Central
/NW Data from North West (Seattle and
Bellingham)
/OR Data from Olympic Region (Tacoma)
/SC Data from South Central region
(Yakima)
/SW Data from South West region
(Vancouver)
The region folders might be empty if the region has not deployed data collection equipment or the equipment they are using is not capable of producing public data. There are additional sources of data such as the WSDOT annual traffic report. There is also a traffic data API located at http://wsdot.wa.gov/Traffic/api/ .
There may be several sub-folders underneath the region folders.
/Traffic/NW/FlowData This
folder contain real time traffic data
/Traffic/NW/FlowData/1Minute Contains traffic
data updated every minute
/Traffic/NW/FlowData/5Minute Contains traffic
data updated every 5 minutes
/Traffic/NW/FlowData/20Second Contains traffic data updated every
20 seconds
/Traffic/NW/Bellingham Contains data for the Bellingham sub region
/Traffic/NW/FreewayData This
folder contains archive traffic data
/Traffic/NW/FeewayData/Tools Contains programs
for processing the data archives
Data, Filenames, and Extensions
Filenames are meant to be descriptive and give clues to their contents. The file “MinuteDataDefnOR.xml” has data station descriptions (Defn – definitions) in XML format for the Olympic region. The file has a corresponding data file “MinuteDataOR.xml”. Extensions such as .new, .old, and .junk are temporary files that are not intended to be read.
When using real time data, a program should read a “definition” file first.
<?xml
version="1.0" ?>
<station_def time_stamp="Tue Sep 25 05:31:30 PDT 2012">
<station_version>647</station_version>
<station_count>1220</station_count>
<station id="016es01545:MME___1">
<route>16</route>
<direction>EB</direction>
<milepost>015.45</milepost>
<location>SR-16 @ SR-302</location>
</station>
The first few lines in the file reveal when the data was collected, the version number of the database, and the number of data elements (detectors and stations). The corresponding data file contains the same information. When reading real time data first read and parse the definition file, then read the data file. Compare the version numbers. If you read a data file and the version number is different, then re-read and parse the definition file. DON’T CONSTANTLY READ THE DEFINITION FILE!
Data Definitions:
Version - An integer number that relates the database and data files.
DateTime - The date and time the contents of the file were created.
Count - The number of stations contained in a file.
Station - A point on a road that contains one or more lanes of traffic.
Volume - A count of all vehicles that crossed the lanes in a station.
Occupancy - The percent of time that the station sensed a car in the time period.
Speed - Average speed at the station in miles per hour.
Name - Name of the station in the form RRResMMMMM where R is the State
Route number, “es” stands for electronic sensor, and M is the milepost to the nearest 1/100 of a mile.
Location - A text description of the cross street nearest the cabinet.
Milepost - The milepost of the cabinet to the nearest 1/100 mile, not the station.
Lanes - Number of traffic lanes in the station.
Station name 005es13969:_MN___1 is located on I-5 northbound at milepost 139.69. The device is a single lane detector located on the I-5 mainline. _MN___1 is the device name and includes 7 characters. Characters from left (1) to right (7):
Character 1 designations of ‘D’ are for extra detectors and should not be used in most real time applications. If characters 5, 6, 7 = Stn, the station is an aggregation of multiple lanes. Usually a station contains devices of “__1”, “__2”, “__3”, “__4” to the greatest lane in the cabinet. Character 5 designations of ‘P’, ‘D’, ‘Q’, and ‘A’ are for the ramp meter systems. Data from the Passage loop is considered that most accurate for an on ramp. The ‘O’ designation is for an on ramp that is not metered. Typically, a real time application should use stations of “_Stn” for mainline roadways and ramps should be O, X, and P.