Vehicle counter
Vehicle flow counter, designed as an input for road noise calculation.
Declared error is about 10% on the flow. Because noise is logarithmic, that works out to roughly 0.4 dB on the calculated level — inside the uncertainty of any prediction model, and below the error introduced by estimated speed or road surface type.
Positioning: accuracy adequate for acoustic calculation, not a general-purpose traffic counter. Transport engineering would need better than 95%, and the instrument is not suitable for that.