An anti-collision device system (ACDS) is a safety technology designed to prevent collisions between vehicles, trains, aircraft, or other moving objects by detecting potential hazards and taking preventive actions (alerting, braking, or steering automatically). Below is a comprehensive overview, with a focus on its most prominent use in Indian Railways (Kavach), as well as other applications.
1. Kavach – India’s Indigenous Train Anti-Collision System
Developed by Research Designs & Standards Organisation (RDSO) in collaboration with Indian industry.
How Kavach Works
Component
Function
RFID Tags on tracks
Identify location, speed limits, signal aspects
Onboard Locomotive Unit
Processes data, controls braking
Stationary Units (at signals, level crossings)
Communicate real-time signal status
Radio Communication (UHF)
Between loco, station, and other trains
Key Features
Automatic Brake Application if driver fails to respond (SPAD prevention)
Train-to-Train Collision Avoidance (within 3–5 km range)
Prevents derailments due to over-speeding
SOS & Whistle Control at level crossings
Real-time monitoring via central control
Versions
Version
Capabilities
Kavach 3.2
Basic collision avoidance
Kavach 4.0 (Latest – 2025)
AI-based predictive analytics, 4G/5G integration, drone-assisted track monitoring
Deployment Status (Nov 2025)
Operational: ~5,000+ km (South Central, Western, Southern Railways)
Under Implementation: 25,000+ km target by 2027
Cost: ~₹50 lakh per km
2. Other Anti-Collision Systems
Domain
System
Technology
Automotive
AEB (Automatic Emergency Braking)
Radar, LiDAR, Camera

FCW (Forward Collision Warning)
Alerts driver

ADAS Level 2+ (Tesla, Mercedes)
Full auto-braking + lane keep
Aviation
TCAS (Traffic Collision Avoidance System)
Transponder-based
Marine
AIS + Radar ARPA
Automatic vessel tracking
Industrial Cranes
SICK/Laser Scanners
Zone-based proximity alerts
3. Working Principle (Generic)
Detection → Sensors (Radar, LiDAR, RFID, GPS)
Prediction → Calculates Time-to-Collision (TTC)
Decision → Alert → Warn → Act (brake/steer)
Feedback Loop → Post-event data logging
TTC Formula:

4. Advantages & Challenges
✅ Advantages
❌ Challenges
Prevents human error
High initial cost
Real-time protection
Requires infrastructure (e.g., RFID tags)
Data for predictive maintenance
Interoperability issues
Reduces insurance claims
Cybersecurity risks
5. Future Trends (2025–2030)
AI-Powered Predictive Collision Avoidance
V2X Communication (Vehicle-to-Everything)
Satellite + 5G Integration (for remote areas)
Drone-Assisted Monitoring (Indian Railways testing)
Want to Know More?
For Indian Railways Kavach: RDSO Website
Automotive ADAS: ISO 26262 standards
DIY/Prototype: Use Arduino + Ultrasonic + Servo for basic model
Let me know your specific use case (trains, cars, drones, etc.), and I’ll give a customized deep dive!