Average Daily Traffic Counts Map

This dataset contains the Average Daily Traffic counts and AM and PM peak hour Traffic counts measured on various road segments in the City of Cambridge from 1972 to 2017. The counts in this data set reflect only vehicle counts. An Average Daily Count measures the number of vehicles for an entire day, or an average of several days. Automatic Traffic Recorders (ATRs) log every vehicle that passes in each direction and this data is used to calculate Average Daily Traffic volumes and AM and PM Peak Hour Traffic Volumes for the street. The Peak Hour is average highest number of vehicles recorded during the morning and evening peak hour. Not all streets have the same peak hour. For example, the peak hour for one street could be 5 pm to 6 pm, whereas a peak hour for another street could be from 5:15 pm to 6:15 pm. The peak hour for a street can also change from day to day. When counts are done for several days, the Peak Hour count is the average of the highest peak hour over those days.
Automatic Traffic Recorders (ATR’s) are rubber hoses temporarily affixed to the street. When a vehicle passes, a pulse of air passes through the hose and triggers an air switch in a recording device on the roadside. The recorder device is a small steel box powered by a battery. Air switch triggers are stored on board and later downloaded to a computer. Note: Traditional and older ATRs were not able to record bicycles, however, more recent ATR’s (past 5 to 10 years) have been able to record bicycles that pass over the recorder.