Footfall Is Not Scans
A busy street does not guarantee scans. Most passers-by never look at the code, and most who do look decide not to scan. Breaking the journey into footfall, notice, and scan decision makes the bottleneck visible: a code nobody sees needs placement work, while a code people see but ignore needs a better reason to scan.
Using the estimate
Start with conservative rates, compare two or three candidate placements, and treat the winning placement as a hypothesis to test with a short pilot. Once real scans are flowing, replace the assumed rates with measured ones and the estimate becomes a reliable forecast.
