Why so many Requirements?
The number of requirements for a new vehicle product line varies widely based on complexity, regulatory needs, and market positioning. However, here are some general figures:
Traditional Internal Combustion Engine (ICE) Vehicles
50,000 to 100,000+ requirements
Covers mechanical, electrical, regulatory, and safety aspects
Electric Vehicles (EVs)
100,000 to 200,000+ requirements
Includes additional software, battery management, thermal management, and high-voltage safety
Software-Defined Vehicles (SDVs)
200,000 to 500,000+ requirements
Higher complexity due to over-the-air (OTA) updates, software-based functionalities, connectivity, ADAS, and autonomy
Highly Automated / Autonomous Vehicles
500,000 to 1,000,000+ requirements
Integrates AI-driven perception, sensor fusion, redundancy, fail-operational architectures, and extensive regulatory compliance
In modern vehicle development, 40-60% of requirements are software-related, and this share is increasing with SDVs. OEMs rely on requirement management tools (e.g., Polarion, DOORS, Codebeamer) to track and validate these requirements across product lines.
Example: Airbags
The Airbag sub-systems of a car can easily have 50,000-80,000 requirements associated with them. Here is why
1. Functional Requirements
Deployment Logic: When should the airbag deploy? (E.g., frontal impact > 25 km/h)
Multi-stage Deployment: Different force levels depending on crash severity.
Passenger Sensing: Detecting occupants (adult, child, empty seat).
Side Airbags & Curtain Airbags: Coordinated deployment in different crash scenarios.
2. Safety & Redundancy
Redundant Triggering Circuits: Prevent false positives/negatives.
Fail-Safe Mechanisms: System must self-diagnose failures.
Sensor Fusion: Integration with accelerometers, gyroscopes, and radar.
3. Regulatory & Compliance Requirements
FMVSS 208 (USA): Occupant crash protection standards.
UNECE R94/R95 (Europe): Frontal & lateral impact regulations.
China NCAP, Euro NCAP, IIHS: Different rating system compliance.
4. Hardware & Material Constraints
Inflator Chemistry: Must be stable under various temperatures.
Fabric Strength: Must resist wear and environmental degradation.
Connector Reliability: Must withstand vibration and corrosion.
5. Integration with Other Systems
Seatbelt Pretensioners: Airbag must coordinate with them.
ADAS (Advanced Driver Assistance Systems): Adjustments based on predicted impact.
Vehicle Architecture: Different requirements for SUVs vs. sedans.
6. Software & Communication Protocols
CAN Bus Messaging: Ensure proper timing of deployment signals.
OTA Updates: Requirements for software-based calibration.
Self-Diagnostics & Logging: Error codes, sensor failures, and remote monitoring.
7. Testing & Validation
Crash Test Scenarios: Dozens of crash speeds, angles, and occupant sizes.
Environmental Testing: Extreme heat/cold, humidity, aging simulation.
End-of-Line Testing: Every unit must pass factory quality control.
Why 80,000+ Requirements?
Each of these top-level requirements branches into hundreds of sub-requirements, covering:
Component-level details (e.g., inflator pressure curve specs).
Software constraints (e.g., real-time response deadlines).
Testing conditions (e.g., crash test dummies of different weights).
Country-specific compliance differences.
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