The Maryland Truck Volume Maps depict the average percentages of trucks at various locations on Maryland’s roadways by county. Classification data is collected from a percentage of the 3000+ Program (Coverage) Count stations and 79 Automatic Traffic Recorders (ATR’s) throughout the state of Maryland. Program Count data is collected for both directions, at regular locations on a three year cycle (one-third of these are counted each year). Data is collected for continuous 48 hours starting either Tuesday or Wednesday midnight. ATR data is collected on a continuous basis.
The Truck Volume maps have the data represented as percentages of the total traffic volume for the classification counts taken during the years 2005-2007. 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, the 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. A description of the two classes is given on “Description of Classes”. The current Annual Average Daily Traffic (AADT) is shown above the percentages.