Driving safely with ADAS map speed limits

With the European legislation aiming to equip all cars with the Intelligent Speed Assistance (ISA) by 2022 and the New Car Assessment Programme (NCAP) safety rating, we can help combat the issue of speeding. This is where TomTom’s ADAS (Advanced Driver-Assistance Systems) Map comes in: it’s a critical component to ensure the driver’s safety for vehicles with driver-assistance levels, from L0 to L2.

The importance of speed limits goes back to the root problem. Speeding is one of the main causes of traffic deaths and injuries.

According to the European Commission, speeding is a contributing factor in 30% of fatal road accidents.

This is similar in the United States, where 26% of all traffic fatalities were speeding-related in 2018, killing 9,378 people, as shown by the National Highway Traffic Safety Administration (NHTSA).

Speeding not only reduces the amount of time the driver has to react in a dangerous situation, but it also increases vehicle stopping distance, and reduces the ability of certain road safety structures from protecting vehicle occupants in a crash.

One way to mitigate the problem of speeding is by employing speed limit information. Usually delivered through a digital map or a camera, this information is useful to further reduce the possibility of human error, and therefore avert accidents or diminish the harm they cause.

In response to this problem, various companies and organizations have been developing systems which would help combat this use. For example, NCAP – very well known in Europe and Asia – has awarded additional safety points to cars based on systems to counter speeding. NCAP assesses so-called speed assist systems, which would inform the driver of the present speed limit, give a warning when speeding, and adjust to the new speed limit.

The European legislation is taking another step further by aiming for all cars to be equipped with ISA, – a safety feature that makes sure drivers don’t go over a given speed limit by using a combination of cameras and GPS – which would be mandatory in new European cars starting 2022. This includes passenger cars, light trucks and heavy commercial vehicles.

As mentioned above, using cameras is one way of delivering speed limit information – however, sometimes they can misinterpret them or have an obstructed view. Camera-based image recognition can thus lead to errors when the camera cannot correctly recognize speed limit signs.

For example, speed limits signs from adjacent roads – such as a petrol station next to a highway – can result in the incorrect speed limit information due to skewed camera observations. This is also applicable to situations of conditional or implicit speed limits, like a highway or a city sign without an attached speed limit.