Since 7 July 2024, every new car, van, bus, and truck registered in the European Union has had to carry intelligent speed assistance. On 16 July 2026, the UK government confirmed that Great Britain will require it too.
The idea is simple: the car knows the speed limit and tells the driver when they go over it. The system is only as reliable as the speed limit it works from, and that number comes from a camera, a map, or both. This article covers what the rules require, where the car gets the limit, and what our measurement of open speed limit data across Europe shows about why ISA still gets it wrong.
What intelligent speed assistance does
Regulation (EU) 2019/2144 defines ISA as a system to "aid the driver in maintaining the appropriate speed for the road environment". In practice, the car works out the current limit, shows it on the dashboard, and gives feedback when the driver exceeds it.
ISA is a driver assistance system. The driver can always go faster than the speed the system suggests, and stays responsible for the speed of the vehicle.
What the EU rules require
Article 6 of the regulation sets five minimum requirements.
| Requirement | What Regulation (EU) 2019/2144 says |
|---|---|
| Feedback | The driver is made aware, through the accelerator or other dedicated feedback, that the limit is exceeded |
| Switch-off | The driver can switch the system off, and it returns to normal operation every time the vehicle is started |
| Speed limit source | Road signs and signals, infrastructure signals, or electronic map data, or both |
| Override | The system does not prevent the driver from exceeding the prompted speed |
| Accuracy | Performance targets must avoid or minimise the error rate under real driving conditions |
The Commission's Delegated Regulation (EU) 2021/1958 adds the test procedures and lets manufacturers choose one of four kinds of feedback:
- Cascaded acoustic warning. A visual signal, backed up by a short sound if the driver stays over the limit.
- Cascaded vibrating warning. A visual signal, backed up by a vibration.
- Haptic feedback through the accelerator pedal. The pedal pushes gently back against the driver's foot.
- Speed control function. The car reduces propulsion power, and the driver overrides it by pressing the accelerator a little further.
Key dates for ISA in Europe and the UK
| Date | What changed | Where |
|---|---|---|
| 6 July 2022 | ISA required for type approval of new vehicle types | EU |
| 7 July 2024 | ISA required on every newly registered car, van, bus, and truck | EU and Northern Ireland |
| 7 July 2026 | Advanced driver distraction warning required on every new registration | EU and Northern Ireland |
| 16 July 2026 | UK government confirms ISA among 18 technologies for GB type approval | Great Britain |
| Entry into force + 12 months | ISA required for new GB vehicle types | Great Britain |
| Entry into force + 24 months | ISA required on new GB registrations of complete vehicles | Great Britain |
The GB government response reported more mixed views on ISA than on most of the other 18 technologies. Respondents raised real-world performance, usability, and suitability for GB roads. Support still outweighed opposition. Most of those concerns come back to one question: how the car knows the limit.
Where the car gets the speed limit
There are two sources, and each fails in its own way.
The camera reads speed limit signs as the car passes them. It sees new signs and temporary limits at road works on the day they go up. It also misses signs hidden by lorries, snow, or foliage, and it can pick up a sign meant for a slip road or a parallel road.
Supplementary plates are harder. A limit that applies only to lorries, only when the road is wet, or only between 07:00 and 19:00 requires the system to read and interpret the plate under the sign.
Some limits are never posted as a number. In many European countries, a town entry sign sets the urban default limit, usually 50 km/h. A 30 km/h zone sign covers every street in the zone without repeating the limit at each junction. A camera that only reads round speed signs cannot see either limit.
The map stores a speed limit for each road segment. It knows limits that are never signposted, and weather does not affect it. It is only as current as its last update. When Paris moved most of its streets to 30 km/h in August 2021, and when Wales lowered the default limit on restricted roads from 30 mph to 20 mph in September 2023, every stored map had to catch up. A map also cannot know the value on a variable motorway sign that changes with traffic.
Many systems combine the two sources and use each to check the other. That makes the quality of the map layer matter, even in cars with a good camera.
Speed limit coverage in open map data
Carmakers license commercial map data or build their own, and those datasets are not public. OpenStreetMap is the speed limit layer anyone can measure, so we measured it.
Method. We counted road segments ("ways") in OpenStreetMap that carry an explicit maxspeed tag, split by road class. European numbers come from the Geofabrik taginfo instance for Europe, and worldwide numbers from the main OpenStreetMap taginfo. Both use data up to 10 September 2026.
| Road class | Ways in Europe | With maxspeed | Share in Europe | Share worldwide |
|---|---|---|---|---|
| Motorway | 340,949 | 327,939 | 96.2% | 65.9% |
| Trunk | 530,905 | 451,455 | 85.0% | 57.3% |
| Primary | 1,666,193 | 1,304,565 | 78.3% | 59.5% |
| Secondary | 2,519,826 | 1,707,072 | 67.8% | 49.1% |
| Tertiary | 3,626,140 | 1,805,652 | 49.8% | 30.2% |
| Residential | 15,192,295 | 4,264,797 | 28.1% | 9.8% |
| Unclassified | 4,909,514 | 925,550 | 18.9% | 7.3% |
Three findings stand out.
Europe is well mapped where speeds are highest. 96.2% of motorway ways carry a speed limit, against 65.9% worldwide.
Coverage falls with road class. Fewer than 3 in 10 residential ways and fewer than 1 in 5 unclassified ways in Europe have an explicit limit. These are the streets where 30 km/h zones, school streets, and town entry defaults apply.
Two values dominate. Of all European ways with a maxspeed tag, 29.0% say 50 km/h and 25.5% say 30 km/h.
What these numbers do not measure:
- A missing tag does not always mean an unknown limit. Many residential streets follow a national urban default that software can infer from the country and the town boundary. Mappers can record the type of limit with
maxspeed:typeorzone:maxspeed, which appear on 3.6% and 1.9% of European residential ways. - We counted ways, not kilometres. A way can be 20 metres or 20 kilometres long.
- A tag records what a mapper entered. It does not show whether the value is still correct today.
- Conditional limits are tagged, but rarely. 77,929 ways in Europe carry
maxspeed:conditional, for limits that depend on time, weather, or vehicle type.
What good speed limit data looks like
Whether the data comes from a camera fleet, a survey, or open mapping, the same properties make it usable for ISA, fleet software, or navigation.
- An explicit value with a unit. 30 km/h and 30 mph are different limits, and the data must say which.
- A value per direction. Limits can differ by direction on the same road.
- The reason for the limit. A value read from a sign and a value inferred from a national default carry different confidence. OpenStreetMap records this with
source:maxspeedandmaxspeed:type. - Conditions as structured data. Time windows, wet weather limits, and limits for lorries or trailers should be machine-readable, in a format such as
maxspeed:conditional. - Zones as well as segments. A 30 km/h zone is one rule that covers many streets.
- Freshness. New limits should reach the data within days, with an edit date that shows when each value was last confirmed.
What ISA means beyond the car
Fleet operators and telematics software face the same problem ISA solves in the car. A speeding report needs the limit on the road segment the vehicle actually drove. That starts with map matching, which snaps each GPS point to the right road, because a point between a motorway and its slip road can belong to either.
Automated driving needs the same information at lane level, which is where HD maps come in.
ISA shows the speed limit but says nothing about enforcement. Our free speed camera map shows fixed, red light, average speed, and variable limit cameras by country, and the traffic enforcement cameras article explains where that data comes from and what it cannot tell you.
Where MapAtlas fits
The MapAtlas Map Matching API turns raw GPS traces into the sequence of road segments a vehicle drove, with a confidence score for each matched segment. That is the step any speeding or driver behaviour report builds on.
Questions fréquemment posées
What is intelligent speed assistance?
Intelligent speed assistance (ISA) is a driver assistance system that tells the driver when the vehicle exceeds the speed limit. It works out the limit from a forward camera that reads road signs, from speed limit data in the car's digital map, or from both. Depending on the car, it warns with a sound or a vibration, pushes back through the accelerator pedal, or reduces power. The driver can always override it.
Is intelligent speed assistance mandatory?
In the EU, yes. Under Regulation (EU) 2019/2144, new vehicle types have needed ISA for type approval since 6 July 2022, and every newly registered car, van, bus, and truck has needed it since 7 July 2024. The same rules apply in Northern Ireland under the Windsor Framework. Great Britain does not require ISA yet, but on 16 July 2026 the UK government confirmed it will add ISA to GB type approval.
Can you turn off intelligent speed assistance?
Yes. The EU regulation requires that the driver can switch the system off, but ISA must return to normal operation every time the vehicle is started. The driver can also exceed the prompted speed at any moment. In cars that use the speed control function, pressing the accelerator pedal a little further overrides the power reduction.
How does intelligent speed assistance know the speed limit?
The regulation allows two sources: observation of road signs and signals, and infrastructure signals or electronic map data. Many cars combine a forward camera that reads signs with speed limits stored in the navigation map. The camera catches new and temporary signs, and the map covers limits that are never signposted as a number, such as the default limit that starts at a town entry sign.
When will intelligent speed assistance be mandatory in the UK?
In Northern Ireland it already is, because EU vehicle safety rules apply there. For Great Britain, the government response published on 16 July 2026 plans to require ISA on new vehicle types 12 months after the legislation enters into force, and on new registrations of complete vehicles 24 months after entry into force. No entry into force date has been set yet.
