Get ahead with ISA: Safer driving with accurate speed limits

What is ISA and why is it needed?

From July 2022, Intelligent Speed Assistance (ISA) will become mandatory in new vehicles in the EU and some other countries.

The legal speed limit will have to be visible to drivers at all times, even when there is no clear road sign on view – and it must be at least 90% accurate according to EU law.

Cars fitted with cameras can pick up the information from road signs. However, when no road sign is available, when it is obscured from view, for instance, maps are needed. Some speed limits are implicit, meaning that they are determined by local rules and there are no road signs.

Drivers will be shown the speed limit at all times and will receive some kind of alert if they exceed it.

“It is really down to the car manufacturers how they want to provide this feedback to the driver," said Sjoerd Spaargaren, HERE Product Marketing Manager for Automated Driving. “The key thing is that there is some sort of visual representation of the speed limit in place."

The EU hopes putting these alerts in all new cars will help tackle casualties on the roads. It is estimated ISA will reduce collisions by 30% and deaths resulting from collisions by 20%. This could make a big difference when you consider that nearly 30% of deaths on the roads are caused by speeding.

How does ISA work?

Alerts can be sent to the driver in the form of a sound, a visual cue or even a vibration on the steering wheel. If the driver chooses, they can override the ISA alerts, but the important thing is that they will be informed of the speed limit and warned if they have gone too fast.

“The main reason to implement this is to make the driver aware of whether he is overspeeding or not," Spaargaren said. “Drivers are not always aware of the local rules and regulations."

Conditional speed limits that change at specific times of day or in specific weather conditions can make it more complex for drivers. Added to that the fact that the law can change over time, and it is not easy to figure out how fast you can legally drive.

“In the Netherlands for instance, our maximum speed limit was 120 kph for decades," Spaargaren explained. “It was increased to 130 kph on some highways, then reduced in 2019 to 100 kph because of the impact on emissions. However, there is a time after which you can go faster than that, although it is not easy to read those details on road signs."

He said feedback from several HERE customers showed that only with a camera and a map working together could they achieve the 90% or more accuracy demanded by the EU mandate.

And it is not just cars that will have to display the speed limit. Heavy vehicles, trucks, buses and small, light commercial vehicles will also have to comply. 

Some countries outside of the EU such as Turkey and Israel have also been looking at introducing similar regulation, while car manufacturers in other territories are introducing the technology even without a mandate. Norway and Switzerland will introduce ISA despite not being included in the 27 countries legally bound by the EU ISA regulation.

ISA is one of many Advanced Driver Assistance Systems (ADAS) that are gradually being introduced to cars. They include parking assistance tools and lane departure warnings. For the EU, ISA is part of a package of regulation that is gradually being introduced as part of its Vision Zero effort to eliminate collisions altogether by 2050.

As automated vehicles become more advanced, ADAS tools could be used by the car to make decisions instead of the driver. For example, the car could slow down when it is approaching a sharp bend in the road.

“The aim is to make roads much safer, not only from the driver perspective, but also for other vulnerable road users like pedestrians and cyclists, etc. Anything we can do to help is worthwhile," he added. “There is a long way to go but the possibilities are exciting."