How risk tolerance shapes ADAS regulation: The U.S. and European approaches

Regulating vehicle tech is no simple matter. Facing big goals to improve road safety, cars are filling up with active safety technologies and advanced driver assistance systems (ADAS). We have seen massive leaps forward in the capabilities of ADAS tech in recent years, increasing levels of automation and autonomy. As a result, we’ve begun to see closer regulation of this driver assistance tech, but where do we currently stand and what can we expect in the coming years?

As cool as ISA

This year, Europe saw one of its most noteworthy developments in active vehicle safety with several ADAS technologies being mandated as part of the European Union’s General Safety Regulations (GSR).

One of the most talked about and potentially impactful is intelligent speed assistance (ISA). This first came into effect for all new vehicle models in 2022, and to all vehicles in July 2024 — thanks to this mandate, today every vehicle is required to have an ISA system in the European Union.

[Read: Intelligent speed assistance systems are coming, next we need drivers to use them]

Alongside Europe, the United States is another huge market for ISA tech but is not making the same legislative progress — and with a change in government administration, it likely won’t any time soon.

Back in October 2024, ISA regulation in the U.S. received a surprising and major setback after California Governor Gavin Newsom vetoed a bill that would have mandated a form of speed assistance technology in the State.

Usually, California sets the trend in vehicle tech, but carmakers and dealers opposed the bill claiming having different rules in California to every other state would have created confusion. As a result, the bill will be evaluated by the National Highway Traffic Safety Administration (NHTSA) and potentially mandated on a national level. It’s not yet clear when this will be.

Giovanni Giancaspro, Senior Manager Product Marketing at TomTom, says a U.S. ISA mandate could take years as the NHTSA is only at the early stages of evaluating the technology. And the change in government administration won’t help matters.

A difference of approach

Here we see one of the leading differences and most influential dynamics in approaches to ADAS regulation and development between the U.S. and Europe.

“Typically, in the U.S., they allow for freer technological development and innovation. When issues arise or safety concerns are raised, they then begin to investigate regulating the technology,” Stephanie Leonard, TomTom Governmental Affairs Manager, says.

“The key difference between the U.S. and Europe is that in the States regulation is used to prohibit and control technologies, whereas in Europe it’s used to allow and enable,” She adds. In other words, in the U.S., technologies are allowed to develop first, in Europe, technologies must have the buy in of regulators before they make it to vehicles.

Each approach has its pros and cons. The U.S. approach allows technology to develop quickly and uninhibited, but it might be less safe — regulations often must catch up. On the other hand, Europe’s approach ensures when mandated tech reaches the market, it has a clear performance expectation and operates as agreed and intended. However, this approach is often criticized for slowing down innovation and being complex. As we zoom out from ISA, we continue to see this dynamic at play with other forms of ADAS tech.

What about other ADAS tech?

While ISA might not be at the front of its mind right now, the NHTSA is taking other steps to influence vehicle safety in other Level 1 and Level 2 ADAS technologies. In November this year, the NHTSA announced updates to its 5-star new car safety rating system (NCAP) to include pedestrian automatic emergency braking, lane keep assist, blind spot warnings and blind spot intervention. This will take effect for model years 2026 onwards.

“This is good progress and is nice to see,” Giovanni says, “but the overall assessment still trails behind Euro NCAP.” It’s important to note that the NCAP is not a regulatory system, but a consumer information program to help car buyers understand how safe one car is compared to another. In the EU, many of these technologies were mandated as part of the GSR, and have been part of Euro NCAP for many years — automatic emergency braking and lane keep assist/departure warnings were added in 2014.

While programs like NCAP do go some way to explaining the tech for consumers, with all these new ADAS features and ever more advanced L2 systems, the landscape of ADAS tech is still complex — lacking consistency from one carmaker to the next.

Thankfully, on a global scale, the United Nations is setting new regulations to tackle ambiguity and confusion over the capabilities of Level 2 ADAS systems. The aim is to improve safety and encourage the correct use of said systems.

In September 2024, the global political organization adopted a regulation specifically designed to define and mandate the use of highly advanced ADAS systems. Known as Driver Control Assistance Systems (DCAS), the U.N. defines them as “systems which assist the driver in controlling the longitudinal and lateral motion of the vehicle on a sustained basis, while not taking over the entire driving task.”

The regulation states that DCAS are categorized as Level 2 systems, meaning drivers must always pay attention — systems must have effective warning strategies to alert drivers if they don't pay attention. Importantly, the mandate also requires manufacturers to be clear about the capabilities and limitations of their systems in advertising and point-of-sale marketing.

Indeed, many Powerful L1 and L2 ADAS technologies are available to everyday drivers in Europe and the U.S., such as Tesla’s Autopilot, Ford’s BlueCruise, GM’s Super Cruise, Volvo’s Pilot Assist and Hyundai Kia’s Highway Driving Assist, among many others — almost every manufacturer offers such a system.

The issue of safety here is that the tech is now so good that it can appear much more autonomous than it is. This, coupled with autonowashing — a phenomenon where technology is implicitly marketed as being more autonomous than it is — leads many drivers believe these systems to be close to fully autonomous (Level 5).

Misusing a L2 system under the guise of it being L5 has had hugely detrimental results in some cases. When used correctly, L1 and L2 driver assistance technologies do have the potential to dramatically reduce driver stress and improve safety — as this paper explores.

Indeed, when many ADAS features combine and work in unison, they can take complete control of the vehicle, managing its speed and direction. In some cases, they can even navigate, change lanes and come to a complete stop and start up again afterwards. Some systems, which have cameras and other sensors to actively monitor the driver’s awareness, can be used hands-free, under specific conditions.

Thanks to the U.N.’s DCAS directive there should be no confusion that these systems require constant and complete attention from the driver, and that goes for the U.S. and the EU.

What’s more, these rules set a global tone for carmakers and industry suppliers on how far they can push claims of their systems’ capabilities. ADAS and DCAS have the greatest impact on road safety when used appropriately, and that can only happen if drivers fully understand what they are and how to use them. Mandating what technologies a vehicle has and how they work is important, and so is mandating how they are presented to consumers.

Road safety and tolerance of risk

“At the base of it all, it comes down to an almost philosophical discussion about aversion to risk,” Stephanie says. “Countries and jurisdictions, especially in Europe and the UK, are more risk averse than in the United States. So, we tend to see differing approaches in the development and proliferation of technology and its regulations.”

This may go some way to explaining why Europe leads when it comes to unifying tech with regulations. “Without regulations, nothing can be on the roads in Europe,” Stephanie says.

Indeed, in 2023, the British government proposed its Automated Vehicles Bill, a “legal framework for the safe deployment of self-driving vehicles in Great Britain.” The bill covers the responsibilities of manufacturers, protections for drivers, vehicle safety thresholds and assessment, and advertising standards for automated vehicle tech.

Building on this, in 2024, the nation announced the finalized Automated Vehicles Act, enacting the legislation and cementing its approach towards self-driving vehicles. Again, this preemptive work to legislate for technology that’s still on the horizon indicates a more cautious approach.

“In the U.S. we see a different approach to legislation,” Stephanie says. “One that has a larger tolerance for risk, and a greater focus on innovation and technological development. In the States, legislation controls and prohibits, in the EU without legislation or approval new vehicle technologies can’t be on the road.”

The NHTSA is trying to move the conversation towards a coherent framework to guide how automated vehicles should be regulated. But due to the U.S. regulatory structure, enacting and enforcing laws is a responsibility shared across local, state and federal governments making it complex.

The U.S.’s NHTSA and Department of Transport, in 2017, released its Automated Driving Systems (ADS): A Vision for Safety 2.0 document, publishing updates in 2018 and 2020 with AV 3.0 and AV 4.0.

Unlike Britain’s AV Act, these are not pieces of legislature, but federal-level guidance for automated vehicle technology for industry and State bodies. They offer an overview of best practice that should be considered by carmakers, governments and other stakeholders in the automated driving industry — covering elements such as operational design domains, system safety, consumer education and provides recommendations for states developing automated vehicle policies and legislation.

Documents and guidance like this are an indicator of how the automotive industry is changing around the world. They make it easy to observe Europe and Britain’s preference to regulate to allow and enable tech, and the U.S.’s preference to let the technology develop before getting regulators involved.

What next for ADAS and automated vehicles?

“Through technological development and regulation, our vehicles now meet broad and valuable safety standards to deal with accidents when they take place,” Stephanie says. “The next goal is to prevent accidents from ever happening, and that will take a lot of work as technology is developing all around the globe.”

While ADAS technology and regulations have developed at different rates around the globe, progress is being made at the U.N.’s Economic Commission for Europe (UNECE) GRVA (working party on automated and connected vehicles) to define a harmonized safety standard for automated driving systems (ADS) sometime in 2026.

In risk averse nations, we’ll continue to see efforts to unify technology with legislation and expedite the delivery of the most impactful safety technologies to market. In nations with a greater tolerance for risk, we’ll continue to witness swift technological development and see new safety features reach the market, but regulations will come later — and only if they’re deemed absolutely necessary.

Take the example of ISA again — due to it being mandated, it’s a technology we definitely will see in the U.K. and Europe. Even though it’s not mandated in the U.S., we will still see it, but it will likely be offered as a safety feature on high-end vehicles or as an optional extra on lower cost models. When its efficacy and impact on road safety is proven in the real-world, it’s likely that regulators or NCAP programs will pay more attention to it to mandate it for all vehicles.

Those in the industry, like Stephanie and her colleagues, will continue to have their work cut out influencing technological and regulatory development in places like Europe, whilst keeping a watchful eye on the market, industry and public discourse in places like the States.

With the United Nations development goals and Vision Zero road fatality targets guiding the way, any technology that is shown to reduce road incidents will eventually become common place on our roads, that is certain.