Overcome ISA Challenges Using Fresh Map Data

Author: Nico Glorius, Product Manager 

The European Union enjoys the safest roads in the world, and car accidents have declined in the past decade, but there is still progress to be made. In 2020, the EU recorded a total of 18,800 fatalities due to road accidents, which is much higher than the EU goal of 14,800. To enhance road safety, the EU Commission has adopted the Vision Zero and Safe System approach on European roads. This approach prioritizes preventing deaths and serious incidents on the road by adopting laws and regulations and holding awareness campaigns to educate citizens and residents about the importance of abiding by traffic rules. One method that is being implemented is the adoption of Intelligent Speed Assistance (ISA) in vehicles across the European Union.

What is Intelligent Speed Assistance (ISA)?

The Intelligent Speed Assistance (ISA) is an advanced driver assistance system that helps drivers comply with speed limits through appropriate feedback or accelerator control while the driver is still in full control of the driving speed of the vehicle. ISA will soon become mandatory in the European Union in two stages: For new types of cars, vans, trucks, and buses in July 2022 and for all newly registered vehicles starting in July 2024. Additional countries like Norway, Switzerland, and the UK as well as some EU candidate countries have promised to adopt the ISA regulation as well.

Image source: European Transport Safety Council

How can OEMs implement the ISA regulation?

The ISA regulation requires the vehicle to correctly inform the driver of the current speed limit 90% of the time during driving, and at latest two seconds after the vehicle passes the corresponding traffic sign. The system needs to be operational on any road within the EU, and must not rely on map data or online connectivity. Furthermore, OEMs must ensure the reliability of the system for at least 14 years after the car has been manufactured.

For OEMs, this means an obligation to comply with the ISA regulation by always displaying the legal speed limit to the driver as the minimum requirement. When needed, it may also include an audible alert or active limitations of speed by choosing one of the four following feedback methods to base their ISA systems on:

  • A haptic feedback system which relies on the pedal restoring force gently pushing back the driver’s foot in case of over-speed
  • A speed control system that relies on engine management and automatically reduces the propulsion power independent of the position of the driver’s feet on the pedal
  • A cascaded acoustic warning system that flashes an optical signal and in case the driver doesn’t react within several seconds activates an acoustic warning
  • A cascaded vibration warning system that flashes an optical signal and in case the driver doesn’t react within several seconds starts the vibration of the pedal

However, all the above features will cause a bad experience for the end-user if the system determines and uses the wrong speed limit. This can either be through detecting a speed limit that is too high which may lead to a speeding ticket, or through detecting a speed limit that is too low, which may lead to undesired braking.

What makes map data a must-have for overall ISA user experience enhancement?

To comply with ISA, camera detection is the first option for OEMs, but camera-only systems are not able to detect all speed limits at all times. One reason is that not all speed limits are signposted explicitly. For example, speed limits depend on the road type (e.g. motorways, urban roads, living streets, etc.), the time of day (e.g. 100km/h on highways in The Netherlands during the day but 130km/h during the night) or weather conditions (e.g. 110km/h on highways in France during rain). These speed limit rules vary between the different countries in Europe and may suddenly change when crossing European boarders.

Another reason is that even explicit speed limits may be hard to be correctly detected by camera due to obstruction or bad lighting conditions. There are also small conditional signs attached to the speed limit sign that makes the detected speed limits invalid under certain conditions. Although these conditional signs are not part of the ISA regulation, they of course influence the user experience if not detected and applied correctly.

Due to the reasons mentioned, the usage of up-to-date map data will become a must to complement the camera-based system. On one hand, map data can support camera detection in situations where the signs are hard to read and provide information on implicit speed limits. On the other hand, due to newly added or changed signposts, temporary road works, and country-specific regulations, the speed limits can be constantly changing, which requires the map data to be updated frequently.


To meet the ISA requirement of a 90% success rate, fresh map data is necessary since camera-based systems are unable to reach the desired level of accuracy. Using high-frequency updates or an online service can support the correct detection of variable speed signs e.g. on highway gantries, and thus improve the overall user experience.

NavInfo Europe offers map data services based on multiple commercial and open sources that are tailor-made to support the different needs of our customers. Our flexible and reliable solutions provide the required up-to-date map data to the end customers while minimizing data consumption.

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