Safety, Redundancy & Cybersecurity – Building Trust into Autonomy

No matter how smart an autonomous vehicle is, trust is earned through reliability, safety, and resilience. When machines are expected to operate without human oversight, every component – from steering systems to software modules – must prove it won’t fail. Or if it does, that it will fail safely.

In this blog, we go under the hood of the safety frameworks, redundant system designs, and cybersecurity principles that form the backbone of trust in autonomy. Because without safety, there is no autonomy. Only risk.

Functional Safety: Designing Against Failure

Functional safety is not about avoiding accidents. It’s about ensuring that even in the event of a fault, a system behaves predictably and without harm. For autonomous driving, this means every function must comply with standards like:

• ISO 26262: Functional safety of electrical and electronic systems in road vehicles
• SOTIF (ISO/PAS 21448): Safety of the Intended Functionality – addressing what happens when sensors work as designed but fail in perception (e.g. glare, fog)
• UL 4600: The safety case standard for autonomous systems, focusing on full system behavior without a fallback human

Arnold NextG’s NX NextMotion system was developed from the ground up to be ASIL-D/SIL 3 compliant – the highest level of safety integrity under ISO 26262/ ISO 61508.

“In Level 4, you don't design to avoid failure. You design to operate despite failure.”
- Dr. Thomas Schneider, Functional Safety Expert at AVL

Redundancy: If One System Fails, Another Must Take Over

Redundancy is the cornerstone of safe autonomy. In this context, it means:

• Dual or triple control paths (e.g., multiple ECUs, sensors, power supplies)
• Watchdog monitoring (a system checks another’s behavior)
• Fallback mechanisms (alternate steering/braking control, emergency stop modes)

In Arnold NextG's architecture, Drive-by-Wire systems are not only duplicated—they are physically and logically separated. This reduces the chance of a single fault affecting both systems and allows for fail-operational behavior, meaning the vehicle can safely continue its mission or reach a safe stop zone.

This level of design is crucial in applications like:

• Military convoys where human risk must be minimized
• Public shuttles operating without a safety driver
• Harbor logistics where constant operation is critical

Cybersecurity: Safety Doesn’t End at the Hardware Layer

Safety and cybersecurity are two sides of the same coin. If a system can be compromised remotely, its safety is no longer guaranteed.

The UNECE has mandated cybersecurity frameworks for all new vehicle types under:

• UNECE R155: Cybersecurity Management Systems (CSMS)
• UNECE R156: Software Updates and Over-the-Air Integrity

This means every vehicle must:

• Monitor for unauthorized access attempts
• Ensure integrity of software updates
• Maintain audit trails for post-event analysis
• Segment internal networks to isolate critical subsystems (e.g. braking, steering)

Arnold NextG integrates these protections at both hardware and protocol level, including SAFE_CAN encryption, isolated safety domains, and secure boot functions.

Certification: Proving Safety, Not Just Claiming It

In regulated markets – like Europe, North America, or defense mobility – certification is mandatory. That includes:

• Type approval per UNECE and ISO standards
• End-to-end documentation of failure modes, fault injection tests, and safety cases
• Validation under real and simulated conditions (e.g. PEGASUS, ASAM OpenSCENARIO)

Arnold NextG provides full safety documentation and certification-ready platforms for OEMs, system integrators, and mobility operators. 

Trust-by-Design: The New Paradigm

In a world moving toward driverless mobility, trust must be embedded in design, not added afterward. That means:

• Redundant control
• Secure communication
• Certified software paths
• Transparent logic
• Predictable failure behavior

Only then can public transport operators, logistics firms, defense ministries, and regulators say: Yes, we trust this vehicle to operate safely – without a driver.

Conclusion: Safety Isn’t a Component. It’s the System.

Autonomous driving will never be about “perfect software” or “advanced AI.” It’s about creating systems that acknowledge imperfection – and are built to operate through it. Functional safety, redundancy, and cybersecurity aren’t optional – they are the pillars upon which trust, scalability, and real-world autonomy stand.

In the next part of our series, we’ll explore how infrastructure and connectivity – from 5G to remote control centers – support autonomy far beyond what’s on board the vehicle.

References

• ISO 26262, ISO/PAS 21448 (SOTIF), UL 4600
• UNECE R155 and R156 on Cybersecurity and Software Updates
• FMVSS vs. ISO & ECE Certification Comparison, 2024
• BMDV (2024), Handbuch Autonomes Fahren – Öffentlicher Verkehr