SmartTraffic

SIH PS90 — Adaptive Smart Traffic Signal Control

SmartTraffic is a local-first traffic-control prototype focused on a clear single-junction A/B demonstration: the same intersection and the same seeded vehicle arrivals are run under a conventional fixed-clock signal and under SmartTraffic's adaptive controller. The browser visualizes both simulations side-by-side with proper signal phases, queue spacing, and POV/bird's-eye views.

Current judge-facing demo

• One physical intersection shown twice side-by-side.
• Left: conventional fixed-clock signal timing.
• Right: SmartTraffic adaptive-predictive controller.
• Both sides receive the exact same deterministic arrival schedule.
• Proper N/S green, amber clearance, and E/W green transitions.
• Queue-positioned cars with fixed spacing so vehicles do not overlap.
• North/south surge, east/west surge, and balanced scenarios.
• Average queue, wait, throughput, peak queue, and current queue comparison.
• POV and bird's-eye camera modes.

The wider repository still contains network-level controller experiments, SUMO/TraCI adapters, emergency priority work, and benchmark services for future expansion. The main browser demo is intentionally single-junction so the comparison is easy to understand and defend.

Run locally

SmartTraffic is not dependent on Vercel or any hosted backend. Run the backend and frontend in two terminals.

1. Backend

From the repository root:

cd backend
python -m venv .venv

Activate the environment:

Windows PowerShell

.\.venv\Scripts\Activate.ps1

Windows Command Prompt

.venv\Scripts\activate.bat

Linux/macOS

source .venv/bin/activate

Then install and start FastAPI:

pip install -r requirements.txt
uvicorn app.main:app --reload --port 8000

Check the backend directly in your browser:

http://localhost:8000/health

For the single-junction comparison API:

http://localhost:8000/api/single-junction/comparison?steps=100&seed=7&scenario=north-surge

Both URLs should return JSON.

2. Frontend

Open a second terminal:

cd frontend
npm install
npm run dev

Open the Vite URL shown in the terminal, normally:

http://localhost:5173

The frontend connects directly to:

http://localhost:8000

You can override it with VITE_API_URL if needed.

If the browser says BACKEND OFFLINE

1. Confirm uvicorn app.main:app --reload --port 8000 is still running.
2. Open http://localhost:8000/health manually.
3. If that page does not return JSON, fix/start the backend first.
4. Return to the frontend and click Reconnect backend.

The frontend now reports the actual backend URL instead of showing an ambiguous JSON/token parsing error.

Single-junction experiment

The endpoint:

GET /api/single-junction/comparison

creates one seeded arrival schedule and feeds the same arrivals into both controllers.

Fixed Clock

• equal timed green windows
• no awareness of queue demand
• amber transition when changing phase

SmartTraffic Adaptive

• compares N/S and E/W queue pressure
• includes recent queue growth in the short-horizon score
• minimum-green hysteresis prevents rapid flickering
• maximum-green protection prevents starvation
• amber transition before changing phase

This makes the A/B comparison reproducible and fair.

Research / expansion path

The wider research track remains:

1. fixed-clock baseline
2. actuated baseline
3. max-pressure baseline
4. predictive pressure control
5. movement-level/network pressure
6. SUMO/TraCI validation
7. real OpenStreetMap junction geometry
8. emergency / ambulance / fire / police priority handling
9. robustness testing across incidents and unseen demand patterns

No mock-simulator result should be presented as a final SIH performance claim. Final claims should come from controlled SUMO experiments using identical scenarios/seeds.