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Possibilities for restricting speed and other functions

May 2022

Vehicle Technology

Speed limits, among other things in front of schools, make an important contribution to increasing road safety
Speed limits, among other things in front of schools, make an important contribution to increasing road safety

The power and speed offered by the vehicles that young people tend to drive create an irresistible desire in some novice drivers to push them to their full potential. Feeling exhilarated because they have a driver's license at last, they just want to drive around, free and "totally autonomous". It is not uncommon, however, for this type of driving to come to a bad end. Sometimes, tragically, this happens during the first few kilometers of the journey.

This risk potential, which is particularly high in the beginner’s stage, can definitely be reduced by technical means. The continual advancement in digitalizing vehicle drives in combination with control equipment is crucial for achieving this. A decade ago now, the first automobile manufacturer presented a ready-to-use solution that can be used to limit the maximum speed that can be achieved to a set value by means of a programmable ignition key when it is used by, for example, a novice driver.

However such a restriction on the maximum possible speed offers no guarantee that what is stipulated by, for example, the German Road Traffic Act with regard to speed in all driving situations, is actually being observed. In Section 3 it states: ‘A person operating a vehicle may only travel at a speed that allows them to be in constant control of their vehicle. In particular, they must adjust their speed to road, traffic, visibility, and weather conditions as well as to their personal abilities and to the nature of their vehicle and its load.’

Observing traffic regulations plays an especially vital role in ensuring increased safety. On certain sections of road, traffic signs indicate particularly dangerous situations and therefore require compliance with a lower maximum permissible speed. Special protection applies to particularly vulnerable groups of people, for example in front of kindergartens, schools, and retirement homes. In the future, in order to further ensure compliance with the speed restrictions in force (in addition to traffic controls, which are also effective), there will also be on-board devices that will directly have an impact upon adherence to speed limits.

Speed limitation
A speed limiter can be used to set the speed that should not be exceeded when driving


These devices include, for example, the Intelligent Speed Assistance (ISA) system. Since the EU expects this to have a positive effect on reducing the number of accidents, it has stipulated that from July 6, 2022, all new vehicle types (cars, vans, trucks, and buses) must be equipped with an ISA system. ISA will then be mandatory in all new vehicles from July 7, 2024. Traffic sign recognition and cruise control (along with speed regulators/ speed limiters) are now increasingly standard in passenger car equipment. ISA will connect the systems in order to assist the driver in complying with the current speed limit. ISA is designed to recognize the current speed limit by using a video camera and/or GPS support. The intelligent speed assistant can be overridden by the driver at any time. In order to gain acceptance, it is also possible to switch ISA off, with the system reactivating every time the vehicle is turned back on.

The driver can override the system using the gas pedal, for example when overtaking when the speed limit changes. Whenever this occurs, the driver will receive a visual and acoustic signal until they reach or drop below the maximum permitted speed. Then the ISA will be reactivated. ISA does not control the speed by applying the brakes, but by reducing the engine power. There is a corresponding visual and acoustic warning for this. It can also increase the resistance from the gas pedal. It is still the driver's responsibility to apply the brake. Automatic braking only occurs if the vehicle has an automated emergency braking system or an adaptive cruise control system on board.

At the moment it is still difficult to say what accident avoidance potential ISA has. But if, for example, half of all registered vehicles in Germany were equipped with the system in 2030, 2.8 per cent of fatal accidents (equal to approximately 100 road deaths) could be addressed with the help of the system. However, this would only apply in situations where the accident would not have occurred if the speed limit had been observed, which is not always the case. The system can only be fully effective if it is always functioning and if the driver is aware of the warning system and actually responds to its cues. What is also clear is that ISA is "only" an assistance system. In other words, the driver is and remains responsible for observing and complying with the current speed limit at all times.


In the future, the basic principle of automatic speed limiters could also be applied to other means of transport such as e-scooters or pedelecs, as long as the appropriate hardware and software is in place. DEKRA sees this as a prime opportunity to reorganize the current coexistence and confusion in areas primarily reserved for pedestrian traffic, which often leads to conflict and accidents, in a mutually beneficial way and without causing any serious hazards. With an automatic temporary speed reduction for e-scooters and pedelecs from 20/25 km/h to walking speed (7 km/h), the desired model of lively, multimodal inner city areas could be successfully realized in the near future.

The extent to which such solutions could also be applied to certain sections of cycle paths and so-called long-distance cycling routes in the future remains to be seen following successful pilot projects. In any case, DEKRA is in favor of the implementation of such projects. A temporary automatic speed reduction of (appropriately equipped) S-pedelecs (capable of 45 km/h) to a maximum of 25 km/h is also being considered here, as this is the speed limit for electric motors in conventional pedelecs, which are already used on all cycle paths. This would put them on an equal footing with bicycles.

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