Traffic sign recognition and ISA: The thing with the Bing

Switch off, please: With Tesla, all you have to do is tap the speed limit symbol on the display. Mercedes and Renault 5 also have a universal switch to deactivate the warning tone when the speed limit is exceeded. This is mandatory for all cars first registered in the EU from July 7 2024. When the vehicle is started, the acoustic system, which is part of Intelligent Speed Assistance (ISA), must be switched on automatically. A closer look reveals that there is a broad spectrum: Some manufacturers manage the design so well that the ISA is a useful tool. For others, however, switching it off is self-defense against the continued annoyance of binging and beeping. What's going on here?

ISA is part of a package of assistance systems that must be fitted to all vehicle types type-approved – i.e. newly introduced or technically revised – since July 2022 and now to all passenger cars registered for the first time in the European Union. Most of them are not questioned: the automatic emergency braking system, for example, is just as little questioned by the public as the so-called reversing assistant, which supports parking with a camera or distance sensors. The most exciting feature is the warning tone when speeding. To avoid any misunderstandings: Speed limits have a purpose. In urban areas, the speed limit is often 50 km/h, in play streets it is set at walking pace, and in the federal state of Bremen you are not allowed to drive faster than 120 km/h on the highway. But that's not the point.

Intrusive sounds, too many mistakes

When drivers feel the need to switch off the ISA, there are usually two reasons for this: Firstly, there are manufacturers who want to ensure attention with the most unpleasant and intrusive sounds possible. Secondly, the traffic sign recognition in some vehicles is dysfunctional. Sometimes a correct speed is recognized, sometimes the symbol on the tarpaulin of a truck trailer is identified as a limit - a false alarm.

A negative example of the first point is unfortunately the Hyundai Ioniq 6, which is first-class in many other respects. The South Korean manufacturer has interpreted Regulation (EU) 2021/1958 particularly strictly. The Ioniq 6 even emits a short beep when a change (!) in speed is identified, for example when a maximum of 70 km/h is prescribed instead of 100 km/h at a junction on a main road. If the speed is exceeded, the Hyundai emits several loud beeps. There is no shortcut to deactivate the system; instead, you have to search for the off switch in a submenu.

Outdated map material, inadequate cameras

Even more unpleasant are cars that identify incorrect speed limits and warn accordingly. Most cars use a combination of the navigation system's map material plus camera-based traffic sign recognition. However, the map material in many cars is only updated every one and a half years. The EuroNCAP association, which awards up to five stars for safety, has included this criterion in its assessment since 2023. Additional points are awarded if no more than three months elapse before an update.

Camera-based systems, on the other hand, are often flawed. For example, a Tesla Model Y does not recognize city signs. As long as FSD (Full Self Driving) based on the US model is not available in the EU, this could remain the case. A low point in the practical tests by heise Autos was marked by the MG4, which identified incorrect speeds so frequently that it had to be switched off. Even in my colleague Martin's Opel Corsa-e, the recognition of traffic signs is so bad that he considers it absolutely useless.

Wonderful - if it works

The BMW iX2, among others, shows that there is another way. With one exception - when the sun was low in the sky, the sign for a variable traffic sign bridge over the freeway was not read correctly - a test car recognized the signs correctly. As a result, it was also quite pleasant to allow the adaptive cruise control to take over automatically. Moreover, a warning tone does not have to be particularly agonizing by law. The aforementioned BMW or, more recently, a VW ID.4 make it acoustically clear when you are driving too fast without the driver immediately feeling a stinging sensation in their ears. That is the description of the new status quo. But what happens next?

Automated means legally compliant

When asked by heise, the Federal Highway Research Institute (BASt) made it clear that assistance systems up to and including Level 2 can always be overruled by humans. This remains the case. There is a change with the spread of automated cars at level 3 and autonomous vehicles at level 4 and 5. The differences are often not clear, so we will briefly outline them again here. These cars can drive autonomously in certain areas - initially on the highway - and under precisely defined conditions. However, the driver must be able to intervene within a very short period of time if the computer is overwhelmed. While the car is driving autonomously, the driver is no longer responsible. Level 3 will become widespread in the medium term.

With level 4, one thing changes: in a precisely defined scenario, the system can handle all situations on its own. Only level 5 means that a car can drive independently everywhere under all circumstances and conditions. Technically, there is an enormous amount of regulation between these levels because the manufacturers, who are liable in case of doubt, will clearly and narrowly define the conditions for a Level 4 model, for example.

More on the topic of autonomous driving

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Of course, every speed limit must be correctly observed for the activated Level 3 as well as for Level 4 and 5. Until then, the car industry has a task. Buyers of cars with inadequate speed assist systems have long been complaining to the respective manufacturers. However, an improvement for existing vehicles is hardly to be expected because the type approval would probably have to be renewed. This usually only happens halfway through the life of a particular car and then only for new cars. For affected owners; therefore, the only option is to switch off the system as an immediate and permanent measure.

(anw)