Euro NCAP data from 2018 show that camera-based traffic sign recognition systems have advanced and were fitted as standard equipment to nearly all new vehicle models tested in 2018. Most of these systems are now able to function under conditional circumstances such as when a lower limit applies in rainy conditions e.g. on French motorways.
Reports of Euro NCAP’s tests carried out in 2018 show results on Speed Limit Information Functions as part of Speed Assist Systems which also include manual speed limiters, Intelligent Speed Assistance and intelligent Adaptive Cruise Control.
The data show that most of the cars tested in 2018 were able to read the conditional subsign for rain and link this to the status of the windscreen wipers to determine the correct speed limit for the rainy driving conditions. The Euro NCAP results also show that Speed Limit Information Systems using both map and camera are capable of understanding most conditional speed limits, such as:
- Warning signs of a speed limit change a certain distance away
- Speed limits based on time of day
- Speed limits with an arrow, for example indicating the speed limit of a motorway exit lane
- Speed limits conditional on vehicle category (for example HGV only speed limit)
- Implicit highway, city and residential speed limits i.e. reading signs that do not show a speed figure but indicate to drivers that they are entering, for example, an urban road, or a motorway. The car then calculates the correct speed based on the known speed limits for such roads in that country.
- Dynamic speed limits (such as on motorways with variable speed limits indicated by digital signs)
New EU vehicle safety standards, which are now in the final stages of being agreed, include a requirement for Intelligent Speed Assistance to be fitted as standard from 2022. The proposed system is overridable.