The vehicle counter's 10%
The Athexo vehicle counter has a counting error of about 10%. We write it here, plainly, because it is the fact you need in order to decide whether the instrument suits the work in front of you.
Why 10% matters little
Noise is a logarithmic quantity. A 10% error on vehicle flow translates into roughly 0.4 dB on the computed sound level. That sits within the uncertainty of any predictive model, and it is smaller than the error introduced by estimated speed or road surface type.
Where not to use it
Transport engineering needs better than 95% counting accuracy. The Athexo vehicle counter is not suitable for that, and we would rather say so before you buy it. Its accuracy is adequate for acoustic calculation, not for general traffic counting.
Frequently asked questions
- What is the accuracy of the Athexo vehicle counter?
- The stated counting error is about 10%. On the computed sound level that corresponds to roughly 0.4 dB.
- Is a 10% error acceptable for an acoustic measurement?
- Yes. Noise is logarithmic, so a 10% error on vehicle flow produces about 0.4 dB on the computed level: within the uncertainty of any predictive model, and smaller than the error from estimated speed or road surface type.
- Can I use the vehicle counter for transport engineering studies?
- No. Transport engineering requires better than 95% counting accuracy, which this instrument does not reach. It is designed for acoustic calculation.
- Why does Athexo state the error of its instruments?
- Because it is the fact that lets you judge whether the instrument fits the job. In an acoustic measurement what counts is the resulting decibel, not the raw count.