How do traffic rules become requirements for ADS?

Where is the link to local rules?

Assessing ADS requires connecting a particular traffic situation with the rule governing it. The EU regulation and both UN instruments provide a regulatory basis for this connection.

Author’s interpretation: identify a specific rule and explain its relevance to the driving task. Then determine the expected system behaviour and how it should be demonstrated. Similar provisions retain different legal mechanisms of application, explained in the UN R185 and GTR26 overview.

Case: speed through a blind bend

Section 16(1) of Slovak Act No. 8/2009 Coll. requires adapting speed to the circumstances and enabling the driver to stop within the distance they can see. Subsection (5) addresses the limit indicated by a sign. Both requirements matter. [9]

Annex II, point 1.1.2(a), of the EU regulation also connects safe speed with respect for speed limitations. [1]

Conclusion for the case: a “no more than 30 km/h” criterion tests observance of the limit. The supplied data do not establish whether speed was appropriate for the bend. Missing evidence does not itself prove that the speed was inappropriate.

How can the rule inform a test?

The following is an authorial method for keeping legal meaning connected to technical verification. Each step should be understandable to someone who did not develop the system.

Simply replacing the limit with an arbitrary 20 km/h target is insufficient. A lower speed may be an appropriate assessment outcome, but it needs evidential support. Likewise, failing a conservative internal criterion does not automatically establish a legal breach: the criterion’s relationship to the legal requirement must first be explained.

Why is a “pass” insufficient?

UN R185, paragraph 7.3.2.16, and GTR26, paragraph 5.3.2.16, require justification of acceptance criteria. Paragraphs 7.3.3 and 5.3.3 respectively connect requirements with claims, arguments and evidence in the safety case. Whether a test assesses a property needed for compliance is therefore legally significant. [2] [3]

The EU regulation’s Annex III, Part 2, also covers acceptance criteria and decision-making under national rules: points 3.5.5.2(c) and 3.5.5.3(v). Point 4.1.1 includes checking real-world behaviour. [1]

Recommendation to the project: first check whether existing records permit an assessment of sight and stopping distances. If so, further analysis may suffice. If decisive data are missing, design supplementary testing to address that gap. Separately identify who has legal authority to require such evidence and through which procedure.

What does application of local law mean?

UN R185 and GTR26 refer to the application of relevant law. The GID proposal used here, GRVA-26-09 section F7, explains this through legal practice and case law. It addresses complex situations and tensions between rules; ordinary human rule-breaking is not permission for a manufacturer to ignore the law. [2] [3] [7]

Author’s interpretation: where a rule is unclear, document the chosen interpretation and remaining questions. Test results can support claims about vehicle behaviour, but cannot themselves resolve a dispute over legal meaning. This approach does not prescribe the algorithm through which ADS must decide.

What follows for legal assessment?

Section 16 is expressed as a driver’s duty. When assessing ADS, the rule’s relevant content informs required system behaviour through the applicable regulatory framework. This does not by itself determine who is liable for an event or who may operate the vehicle. [1] [9]

The assessment should identify the rule, its meaning, required behaviour and evidential scope. When the scenario, software or a decisive assumption changes, examine the effect on these connections. The outcome may confirm the original conclusion, narrow it or identify a need for further evidence.