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This is a Non-Federal dataset covered by different Terms of Use than

MD iMAP: Maryland Annual Average Daily Traffic - Annual Average Daily Traffic (SHA Statewide AADT Points)

Metadata Updated: July 23, 2021

This is a MD iMAP hosted service layer. Find more information at Traffic monitoring data is a strategic resource for SHA and Maryland's Department of Transportation. The data is essential in the planning - design and operation of the statewide road system and the development and implementation of state highway improvement and safety programs. TMS is a product of the ISTEA Act of 1991 - which required a traffic data program to effectively and efficiently meet SHA's long-term traffic data monitoring and reporting requirements. The quality control feature of the system allow data edit checks and validation for data from the 84 permanent - continuous automatic traffic recorders (ATRs) and short-term traffic counts.The Maryland Traffic Volume Maps depict the Annual Average Daily Traffic (AADT) at various locations on Maryland's roadways by county. Traffic Volume data is collected from over 8700 program count stations and 84 ATRs - located throughout Maryland. To date - four (4) ATRs have been removed from the ATR Program. Program count data is collected (both directions) at regular locations on either a three (3) year or six (6) year cycle depending on type of roadway. Growth Factors are applied to counts which were not taken during the current year and the counts are factored based on the past yearly growth of an associated ATR. Counters are placed for 48 hours on a Monday or Tuesday and are picked up that Thursday or Friday - respectively. The ATR and toll count data is collected on a continuous basis. Toll station data is provided by the Maryland Transportation Authority. A special numeric code was added to the AADT numbers - starting in 2006 - to identify the years when the count was actually taken. The last digit represents the number of years prior to the actual count. Where '0' represents the current year when data was collected (in 2014) - '1' represents the count taken in 2013 - '2' represents the count taken in 2012 - '3' represents the count taken in 2011 and so forth. Last Updated: Feature Service Layer Link: ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

Access & Use Information

Public: This dataset is intended for public access and use. Non-Federal: This dataset is covered by different Terms of Use than License: No license information was provided.

Downloads & Resources


Metadata Created Date November 10, 2020
Metadata Updated Date July 23, 2021

Metadata Source

Harvested from md json

Additional Metadata

Resource Type Dataset
Metadata Created Date November 10, 2020
Metadata Updated Date July 23, 2021
Data First Published 2016-07-21
Data Last Modified 2020-01-25
Category Transportation
Public Access Level public
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id d8a90ed5-0983-4031-a35d-4799ccb5b955
Harvest Source Id ee165ef5-7b35-41a7-b3a5-5479c71b0e58
Harvest Source Title md json
Homepage URL
Source Datajson Identifier True
Source Hash 06001bd79022054f3151d6ad4d2928b3fcac7587
Source Schema Version 1.1

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