Daily collection at a highway toll plaza
Flow-rate estimation — count what passes a point.
Estimate the daily toll collection at a busy national-highway plaza (e.g., on a metro-to-metro corridor). This is a flow-rate build: vehicles per lane per hour × lanes × hours × mix-weighted toll.
Flow
A FASTag lane processes ~7–8 vehicles/minute ≈ 450/hour. 8 lanes × ~70% average utilization (night dips, peak surges) ≈ 2,500 vehicles/hour.
Daily count
2,500 × 24 ≈ ~58,000 vehicles/day — sanity: busy NH corridors report 40–80K.
Mix-weighted toll
60% cars (₹120), 30% trucks/MAVs (₹400 avg), 10% buses (₹350) → ~₹227 blended.
Collection
58,000 × ₹227 ≈ ~₹1.3 crore/day (~₹480 crore/year).
How to defend it
The mix-weighting is the differentiator: stating "trucks are a third of traffic but more than half the revenue" shows you understand toll-road economics — it's also why truck-route diversion is the #1 revenue risk in toll concession deals.