CodeDay 2026 · Pitch
ChainBreaker
Stop the toll-plaza chain reaction before it starts.
NH-44 · Srinagar → Jammu
Team of 2 · Built in 2 hours
Live 3D demo + working QR app
Built by
Adeeb & Qasim
Adeeb — engineering & product · Qasim — graphics & design
School
Crescent Public School
Mentor: Bilal Reshi Sir
The Hook
71
vehicles stuck.

Because one driver showed up at Lakhanpur Toll with ₹47 in their FASTag — and a ₹185 toll. Boom stays down for 90 seconds while they pay manually. The queue behind them lasts 3 minutes.

The Problem

A 90-second decline becomes a 3-minute backwave.

1

Tag declined

₹47

Driver of JK 01 AB 1234 reaches Lakhanpur. Balance too low. Boom stays down.

2

Manual payment

90s

Cash, change, receipt. The driver delays themselves and everyone behind them.

3

Queue builds

25 cars

Each car behind brakes harder than the one in front. The queue compounds upstream.

4

Wave persists

3.1 min

The backwave propagates upstream long after the trigger clears the booth.

Mechanics validated by Nagel-Schreckenberg cellular automaton (1992) — a 30-year-old traffic model used worldwide.
The Cost

One stalled car burns far more than ₹185.

Time lost

37.5 person-min

25 vehicles × 90 sec wait, per incident. Multiply by 1,200+ plazas.

Fuel wasted

~0.4 L

Idling vehicles burn ~0.6 L/h. At ~₹2.4 cr/day across India.

CO₂ emitted

0.95 kg

Per incident. 2.31 kg CO₂ per litre of petrol — at scale, tonnes per day.

Emergencies delayed

4–6 min

Ambulances stuck behind FASTag declines. Life-critical seconds lost.

Why It Happens

Traffic waves travel backwards faster than the trigger itself.

Wave speed vs. trigger speed

Each car behind must brake harder and accelerate slower than the one ahead. A 12-second stop at the booth pushes a 3-minute slowdown upstream at ~20 km/h backwards.

We model this with the Nagel-Schreckenberg cellular automaton — accelerate, brake, randomize, move. The simulator is live on screen.

TOLL Wave propagates upstream ← Upstream traffic Trigger
The Fix

Three layers. Zero queues.

5 km geofence warning

App detects you're approaching a plaza with a balance lower than the toll fee. Alert fires before you even see the booth.

Trigger: 5 km out

1-tap UPI recharge

One button → Google Pay / PhonePe / Paytm → balance topped up in under 8 seconds. You never stop, the boom never closes.

≤ 8 sec to settle

Cross-bank ready

Works with HDFC, ICICI, SBI, Paytm FASTags via a single unified API. We sit on top — we don't replace FASTag.

10+ issuer banks
Proof · 3D Simulator

Same plaza. Same driver. Two outcomes.

Without app
[ Screenshot: localhost:3001 — WITHOUT APP / Chain Reaction overlay showing "20 cars stuck" ]
→ Tag declined · 25-car queue · 3-min backwave · honking
With our app
[ Screenshot: localhost:3001 — WITH OUR APP / "FASTag APPROVED — Boom opening" ]
→ 5 km alert · 1-tap pay · boom opens · green cars flow through
Proof · Working App

Scan a QR. Pay the toll. Watch it live.

[ Screenshot: localhost:3010/scan — rear camera scanner with finder reticle ]
1 · Booth scans the tag
[ Screenshot: localhost:3010/tags/FT-JK01AB1234 — QR FASTag card ]
2 · Driver shows their QR
[ Screenshot: localhost:3010/admin — live event stream ]
3 · Admin sees it live
Honest Engineering

What's shipped, what's next.

Today's trade-offs

  • QR stand-in — phones can't read UHF RFID (FASTag uses 860–960 MHz, NFC is 13.56 MHz)
  • QR payload not yet HMAC-signed → replay-attack vector
  • In-memory store — restarts wipe state (dev demo only)
  • Mock UPI flow — no real bank integration yet
  • English-only UI

Next 2 weeks

  • HMAC-SHA256 signed QR payloads with nonce + 30s rotation
  • Postgres + Redis for atomic balance debit at scale
  • Real upi:// deep-link → GPay/PhonePe handoff
  • Hindi + 4 regional languages (Punjabi, Tamil, Telugu, Kannada)
  • NHAI tag API integration · pilot on Lakhanpur (NH-44)
The Ask

Help us put this on a real highway.

Sharp feedback

Tell us what's wrong with the model and the UX. We listen better than we ship.

Mentor intros

Someone who's built fintech in India, talked to NHAI, or shipped a UPI integration.

Toll-operator pilot

One plaza on NH-44 to validate the geofence flow with real drivers and real UPI.

Live during this pitch
1 · 3D Simulator
localhost:3001
2 · Problem deep-dive
site/index.html#problem
3 · Before / After
comparison/index.html
Adeeb & Qasim · Crescent Public School
Mentor: Bilal Reshi Sir · CodeDay 2026 · NH-44 India