The Truck Volume Maps depict the average percentages of trucks at various locations on Maryland’s roadways. Classification data is collected from a percentage of more than 8,700 Program Count stations and 91 Automatic Traffic Recorders (ATRs) throughout the State of Maryland. Program count data is collected (both directions) at regular locations on either a three-year or six-year cycle depending on type of roadway. Growth factors are applied to counts that were not taken during the current year and the counts are factored based on 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.  ATR and toll count data is collected on a continuous basis.

Truck volume maps represent data in percentages of the total traffic volume for the classification counts taken during the years 2020-2022. The truck data is split into two categories according to Federal Highway Administration (FHWA) guidelines: Single Units (classes 4-7) and Combination Units (classes 8-13). In case of multiple counts at the same locations and ATR data, percentages are averaged over the entire data set for that station. The maps show two set of percentages, one next to the other. The first is the percentages of single units and the second is the percentage of combination units. Both are explained in the Description of Classes document (PDF, 111kb). The current Annual Average Daily Traffic (AADT) is shown above the percentages.

See the Truck Volume Map Introduction (PDF, 57 KB) for more information about truck volume maps.

The 2022  Maryland Truck Volume Map (28 MB) is available as a PDF file. To view, download, or print PDF files, you must have Adobe Reader installed on your computer.

To download a free copy of Adobe Reader, click here.

Note on Downloading Time

PDF file sizes for truck volume maps vary. The truck volume map that you select may take a few seconds or a few minutes to display fully; be patient while the file downloads.

To find a truck volume map, click on a county in the map below. A pop-up window with your truck volume map will open. Selecting the arrow pointing to the right opens a window with a hyperlink entitled Truck Volume Map. Click this hyperlink to open the map in your browser for viewing, printing or download.

Truck volume maps from years dating back to 2007 are available by county as PDF files: Archive