Use Case

Intelligent Speed Assistance

Speeding has been a leading factor in road deaths since the invention of the car. Now with advanced technologies, such as Intelligent Speed Assistance powered by digital ADAS map data with speed limits, we are moving into a new era of vehicle safety.

What is Intelligent Speed Assistance, and why does it matter?

Intelligent Speed Assistance (ISA) is a vehicle safety feature. Building on traffic sign recognition technology, ISA informs drivers of the current speed limit and, when needed, acts as a speed limiter – automatically reducing a vehicle’s speed by limiting engine power. ISA is estimated to reduce accidents by 30% and deaths by 20%.

Vehicle safety around the world is measured by the New Car Assessment Program (NCAP) ratings. In Europe, NCAP rewards vehicles with ISA better vehicle safety ratings. Upcoming EU legislation aims to make ISA mandatory for all new vehicles starting in 2022, and mandatory for all existing carlines per 2024. The legislation applies to all European cars, vans, trucks and buses (M and N categories). This makes it imperative for automakers to adopt new safety technologies. So, what are the options and how does it work?

ISA, ADAS and digital map data

ISA can use cameras to identify speed limits through traffic sign recognition. The information is used as input for advanced driver-assistance systems (ADAS) to increase safety through automated driving functions. Cameras, however, have limited range, can be blinded by heavy rain or snow, and perform poorly when needing to recognize conditional and variable speed limits, such as speed limits for specific weather conditions or vehicle types.

The solution is speed limit data from digital maps. ‘Seeing’ beyond camera range and in all conditions, advanced digital map data contains verified speed limit data. The map data fuses with a vehicle’s ADAS function to prepare for changing speed limits. The result is not only greater vehicle safety, but also increased driver comfort and energy efficiency.

ADAS road safety with the TomTom ADAS Map

A major European car brand equipped their vehicles with ADAS functions that incorporate leading TomTom ADAS Map speed limit content. Let’s look at two of the ADAS vehicle safety features.

Traffic sign recognition and intelligent speed control

An on-board camera recognizes speed limit signs. Data is verified by TomTom ADAS Map data, or provided directly if the camera fails. The speed is advised to the driver, and adaptive cruise control can automatically reset to the new speed limit.

Adaptive cruise control

Vehicle speed automatically adjusts to keep a safe distance from the vehicle ahead. Building on intelligent speed control, a fusion of digital map speed limits and camera-based data is used to regulate speed in relation to speed limits.

How it works – ISA and TomTom ADAS Map data

In these vehicles, traffic sign recognition and Intelligent speed control fuse camera input and compare this with the TomTom ADAS Map. Using GPS positioning, the relevant speed limit is extracted from the map. The map data is then exposed via proprietary TomTom software, called Virtual Horizon.

The Virtual Horizon is the road ahead, based on the main path for the current or predicted route. Across this route, the relevant speed limits and traffic signs are exposed, amongst others. The Virtual Horizon is highly configurable to match application needs. It is available in proprietary, or industry standard ADASIS v2 mini and ADASIS v2 formats.

Map data vs. cameras for speed limits

Many speed limit types are nearly impossible for cameras to recognize, such as speed limits conditional on time of day, weather and vehicle type, as well as speed limits with sub-plates and implicit speed limits (e.g. entering a city boundary). TomTom provides highly accurate, verified content for all speed limit types in more than 100 countries.

TomTom ADAS Map speed limits are collected by TomTom survey vehicles and are increasingly maintained with crowdsourced data. We attach these speed limits to specific road segments, also indicating specific validity if it is a conditional speed limit. TomTom quality audits and internal benchmarking against competition confirms the leading quality of speed limit data.

The benefits

To recap, the benefits are many: greater road safety for all, driver comfort, vehicles that meet emerging safety standard legislation, and better vehicle safety NCAP ratings.

Automakers with navigation software supplied by TomTom get an added benefit: our intuitive human-machine interface. Our user interface makes it easy for drivers to stay informed of the correct speed limit at all times.