Analysis - Detector Artifacts Uncovered
Below are a instances where a sidefire radar detector (just
downstream of the loops) detected a “phantom” vehicle in lane 1 when
there was none. Note in all cases there is a semi-truck in a closer
lane. Even the detector developer was apparently unaware of this
VideoSync Analysis - Radar Flow Rate
The graph below was generated by pasting VideoSync tabular
data into Excel. This shows that the total 30 seconds volumes across
5 lanes generated by the radar unit are fairly accurate and the
total “missed” and “phantom” vehicles almost exactly cancel out.
This indicates this radar unit appears adequate during this
period for generating the 30 seconds flow data typically used by TMCs.
Analysis - Radar-Based Occupancy
The bar chart indicates the ratio of the radar occupancy to
real occupancy varies dramatically by lane. The graph shows that
the ratio of the total (5 lane) occupancy to the real occupancy
could vary by almost 20% between 30 seconds sampling periods. This
high variance indicates that this occupancy data is not
functional for most quantitative purposes, even with the
application of a “fudge factor”.