Driving-assistance

systems must

respect traffic laws

Driving-assistance

systems must

respect traffic laws

21/10/2026

A new Belgian study has raised serious concerns about the ability of Tesla’s Full Self-Driving (Supervised) system to comply with speed limits in 30 km/h zones and other low-speed environments. In response, Pedestrian Mobility Switzerland is calling on Swiss authorities not to approve driving-assistance systems that cannot reliably comply with traffic laws. 

The Belgian mobility NGO johanna.be found that Tesla’s “Full Self-Driving” system (FSD) routinely breaks speed limits on roads that are particularly important for pedestrian safety: 30 km/h zones and residential areas (“Begegnungszonen” or “zones de rencontre” – 20 km/h zones).  

Specifically, the researchers found that FSD:

  • Sped through 30 km/h zones in 55% of cases tested, averaging 44 km/h.
  • Misinformed the supervising driver about the speed limit in 90% of those zones, showing “50 km/h” on the internal screen even when the system had correctly read a 30 km/h sign moments earlier.
  • Exceeded the speed limit in 5 of 12 residential areas (“Begegnungszonen” or “zones de rencontre”). In these areas, children are legally permitted to play across the full width of the street.

The researchers also investigated whether inadequate or difficult-to-read signs could explain their findings. To do so, they compared FSD with the conventional traffic-sign recognition system of a Citroën C3 on seven 30 km/h segments. The Citroën recognised the relevant signs correctly in all seven cases, while the Tesla system correctly reflected the speed limit in only one.

Tesla FSD remains a driver assistance system

Despite the name, Tesla’s “Full Self-Driving” is not a self-driving automated vehicle. It is a driver-assistance system that can steer, accelerate, and brake on its own—including through cities—but that requires a human driver to be ready to take over at any moment. Rather than being a fully driverless vehicle, it is in the same broad Level 2 category as other advanced driver-assistance systems now being approved under UN rules for “driver control assistance systems” (DCAS). While these systems may appear highly capable and are often marketed in ways that suggest a high degree of autonomy, they remain legally and technically dependent on a human supervising driver who must stay attentive, responsible and ready to intervene at any moment.

Further concerns

The European Transport Safety Council (ETSC) has raised additional concerns about two speed-related FSD functions: 

  1. “Speed offset” function – This can allow the maximum speed selected for FSD to be set up to 50% above a detected speed limit – meaning it could turn a 30 km/h zone into a 45 km/h limit or a 50 km/h street into 75 km/h. ETSC argues that this is illegal in the context of UN Regulation No. 171, which explicitly states that “the system shall not enable the driver to set a default offset by which the current maximum speed is supposed to exceed the system-determined road speed limit”. 
  2. “Contextual max speed” function – This allows the system to its own speed ceiling/speed limit based on context from its surroundings, including the speed of other traffic. However, if speeding is widespread on European roads, then the speed of surrounding vehicles is not reliable evidence of what the legal limit actually is. A system that raises its own limit because other cars are speeding will only normalise law-breaking behaviour.  

Note: Neither of these functions were active during johanna.be’s tests. 

No Swiss approval without compliance

The recent findings, however, highlight concerns that extend beyond one manufacturer or one particular system. Automated vehicle technology is developing rapidly. While it may ultimately contribute to safer roads, technological progress must not come at the expense of established road-safety standards. This is particularly important in 20 and 30 km/h environments, where people walking and cycling depend on low vehicle speeds for their safety and for the quality of public space.

The FSD technology does not fit into the current EU/UN approval framework, so Tesla’s FSD did not go through the usual EU approval process. Instead, the Dutch vehicle authority (RDW) gave it a provisional approval earlier this year. Lithuania, Estonia, Belgium and Denmark have since chosen to accept this provisional approval. A full, EU-wide approval, however, still requires a vote by Member States in a technical committee, and an update to the relevant UN vehicle regulation.

This has not happened yet – a vote is expected later this year. If EU Member States approve Tesla FSD, the system would become eligible for use on Swiss roads. Pedestrian Mobility Switzerland calls on the competent Swiss authorities to monitor this progress and not to approve driving-assistance systems for use on Swiss roads, unless they can demonstrate that they consistently and reliably comply with applicable traffic laws. No vehicle system should be approved for use on Swiss roads if obeying the law remains optional. 

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