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Annualized, Hourly and Classification count data for the TPB modeled region. Data are collected from state DOTs and processed by TPB staff.
Layers Included
Annualized Traffic Volumes
Historic AADT by Count Station
This database contains the Annual Average Daily Traffic (AADT) estimates reported at permanent and short term counting stations in the TPB modeled region. Please note: Interstates in Virginia are typically represented by two stations (one in each direction) while Interstates in the other states are represented by one station. Therefore, the AADT estimates displayed for the stations on Virginia Intestates will be around half of the total for the directional roadway. The AADT estimates for recent years in this file are based on counts taken at the actual count station locations that are indicated by the station points. The AADT estimates for earlier years are based on volumes reported along roadway segments that the station points currently represent. Specific data sources for each state are listed below:
District of Columbia | AADT estimates since 2006 are based on counts taken at the station locations in the file for purpose of Federal HPMS reporting. | AADT estimates prior to 2006 are based on Traffic Volume maps produced by DDOT (Formerly DC DPW). |
Maryland | AADT estimates since 2000 are based on counts taken at the station locations in the file and reported by MD SHA. | AADT estimates prior to 2000 are based on volumes reported by MD SHA in the Highway Location Reference documents and matched to links in the COG/TPB highway network. The volumes are shown at the count locations that currently represent those network links. |
Virginia | AADT estimates since 1997 are based on counts taken at the station locations in the file and reported by VDOT. | AADT estimates prior to 1997 are based on volumes reported by VDOT in the Average Daily Traffic Volumes documents and matched to links in the COG/TPB highway network. The volumes are shown at the count locations that currently represent those network links. |
West Virginia | AADT estimates since 1999 are based on counts taken at the station locations in the file and reported by WV DOT. |
Traffic Counts by Network Link
This layer was created by assigning the state DOT traffic counting station locations to their corresponding COG/TPB network links. Facility names and route numbers were added to the network. AADT Average Annual Daily Traffic (2016 - 2018), AAWDT Average Annual Weekday Daily Traffic (2016 - 2018) and Count Type (2016 - 2018) are included as well as Single Unit Truck Percent AAD (2018), Combination Unit Truck Percent AADT (2018), Bus Percent AADT (2018, only available for Maryland and Virginia), K Factor (2018), Dir Factor (2018), and Count Year (last year the link was counted). Count Type denotes the source of the count. Please note: for bi-directional roads, the AADT and AAWDT values for each location were divided in two and assigned to both network links that represent the Anode-Bnode direction and the Bnode-Anode direction. Therefore, in most cases the AADT/AAWDT values associated with an individual link in this network will be half of the AADT/AAWDT values reported at the associated individual count station point.
Traffic Counts by External Station
This layer was created by placing points where major facilities cross the TPB Modeled Area boundary. In some cases, the external station represents more than one facility. The facility field indicates which road or roads the station represents. AADT and AAWDT estimates at external stations are provided for 2007 through 2022. Each external station is assigned to a state DOT traffic counting station(s). An effort was made to assign stations or combinations of stations that would come closest to measuring the traffic volume on each facility as it enters/exits the region. In some cases, these volumes are measured just inside the modeled area; in other cases, the volumes are measured just outside the modeled area. The external stations around the Baltimore Beltway are exceptions to this rule. These stations all measure the traffic just south of the Baltimore Beltway in order lessen the influence of traffic specific to Baltimore. AADT Average Annual Daily Traffic (2007 – 2022) and AAWDT Average Annual Weekday Daily Traffic (2007 – 2022) are included. Count Type denotes when the location was last counted. West Virginia does not report AAWDT, so the AADT values were increased by 5% to arrive at AAWDT estimates in West Virginia.