Validating Automated Driving Systems
An Overview of the New Assessment/Test Method (NATM)
Autonomous vehicles are being tested on real roads today. But as automation levels rise, traditional validation methods are hitting a wall — unable to provide the evidence base needed to prove that systems operating independently in unpredictable real-world conditions are truly safe.
The risk? Relying on metrics like miles driven to demonstrate ADS safety — a measure that tells regulators, insurers, and the public very little about what actually matters.
The solution: A structured, multi-layered validation framework built around scenario-based testing, simulation, and continuous in-service monitoring.
Public Trust Requires More Than Innovation. It Requires Evidence.
This white paper provides a comprehensive overview of the New Assessment/Test Method (NATM) developed by UNECE's VMAD working group — the emerging framework shaping how automated driving systems will be validated, approved, and monitored globally.
What Makes This Approach Different
Moves beyond mileage-based metrics to scenario-driven safety evidence
Combines simulation, controlled trials, and real-world testing into a coherent strategy
Integrates in-service monitoring as a continuous safety assurance mechanism
Addresses the fundamental differences between validating ADAS and full ADS
What's Inside This White Paper
The limits of metrics like miles driven as indicators of ADS safety
Why systems that handle rare, high-consequence scenarios require a different approach
The gap between functional testing and real-world operational safety
ADAS vs. ADS: Different Systems, Different Demands
The critical technical and operational differences between ADAS and ADS
What those differences mean for validation strategy, liability, and approval processes
How the shift from driver assistance to full automation changes the assurance burden
The New Assessment/Test Method (NATM)
What NATM is and why UNECE's VMAD group developed it
The four pillars of NATM: scenario-based testing, simulation, real-world trials, and audits
How NATM creates a scalable, repeatable evidence base for ADS safety approval
Scenario-Based Testing and Simulation
How to define and prioritise the scenarios that matter most for safety
The role of simulation in covering edge cases that can't be safely tested on public roads
Combining virtual and physical testing to build a comprehensive validation dataset
Audits and In-Service Monitoring
Why approval is not the end of the safety assurance process
How continuous in-service monitoring detects safety-relevant behaviour after deployment
The role of audits in maintaining regulatory confidence over the vehicle lifecycle
Who Should Read This
Functional safety and validation engineers working on ADAS or ADS programmes
Homologation and regulatory affairs leads navigating UNECE requirements
Systems architects designing safety assurance frameworks for automated vehicles
Programme managers responsible for ADS development and approval timelines