Intelligent Traffic Control System (iVRI) at traffic lights

Municipality of Rijswijk

Whereas traditional traffic lights use detection loops (sensors in the road), amongst other things, to detect the presence of traffic, ‘smart’ traffic lights also use apps to identify the type and volume of traffic approaching. This enables traffic lights to ‘see’ traffic approaching earlier and thus determine how long the green light should remain on.

Last change on 5th of August 2026, at 12:41 (CET) | Publication Standard 1.0

• Publication category: Impactful algorithms
• Impact assessment: Field not filled in.
• Status: In use

General information

Theme

Traffic

Begin date

2017-10

Contact information

[e-mail]

Responsible use

Goal and impact

The aim is to improve road safety, traffic flow and accessibility. It should also help to reduce CO₂ emissions by ensuring traffic flows more smoothly.

The use of iVRIs helps to ensure efficient traffic flow and accessibility at junctions in a safe manner (without people having to wait unnecessarily and by maintaining a logical sequence). It supports the local authority’s mobility objectives. Furthermore, the use of iVRIs is necessary to enable the efficient fulfilment of the local authority’s role as road authority for municipal roads. The algorithm affects road users (motorists, pedestrians, cyclists, lorries, public transport, emergency and rescue services, etc.) because it determines the colour of the traffic lights and how long each road user has to wait.

Considerations

The advantage of using this algorithm is that it allows traffic to flow more efficiently and intelligently. Given the various interests at stake, it is important to consider when one group of road users should be given priority over another. This depends on economic considerations (priority for freight traffic), the environment (residential area, industrial estate, etc.), the preferred mode of transport (priority for public transport and/or cyclists) or necessity (priority for ambulances).

Human intervention

The algorithm makes decisions autonomously in real time. However, the decisions it makes do fall within criteria specified by humans. The local authority can set the parameters itself, for example, how long the traffic light stays green. In addition, the results are monitored and adjusted. This enables the local authority to respond to changing traffic flows.

Risk management

The system complies with all applicable safety requirements and is strictly secured. For example, it is not possible to set all directions to green.

In addition, faults are monitored and the systems are well maintained.

Legal basis

The Road Traffic Act 1994 (WVW) forms the basis for all traffic regulations. The guiding principle is to ensure the smooth flow of traffic and that no one causes a nuisance or poses a danger on the road. In addition, its use has been promoted through the national ‘Talking Traffic’ project and incorporated into the Municipal Policy Plan.

Links to legal bases

• Road Traffic Act 1994: https://wetten.overheid.nl/BWBR0006622/2026-07-01
• Traffic light system: https://wetten.overheid.nl/BWBR0009151/2019-07-01

Operations

Data

The data used by the algorithm is the real-time data measured by the control system itself, using, amongst other things, detection loops and push-buttons. In addition, data is retrieved via the national UDAP. This specific data flow (originating from mobile phones and on-board computers) is classified as (potentially) personally identifiable data. All parties processing this data have signed a data processing agreement.

The core of iVRIs is the integration of various data sources. These include:

1. Sensors: These are installed at junctions and detect the presence and speed of vehicles.

2. Connected vehicles: Modern vehicles often transmit data regarding their location and speed.

3. Mobile apps: Examples include navigation apps that share real-time traffic information.

These data streams are collected and analysed in a central system, where decisions are made regarding traffic light cycles.

Technical design

The traffic light receives signals about approaching traffic. It receives these signals via advanced systems in cars and apps installed on road users’ smartphones. The traffic light receives information about the type of traffic approaching (bicycle, car, lorry) and the volume of traffic approaching. Based on this, a decision is made as to who gets the green light and how long the traffic light remains green. A bus is given a higher priority than a car, and several cars may in turn be given a higher priority than a single lorry.

The way in which the algorithms regulate traffic reflects local decisions.

External provider

Royal Haskoning DHV (RHDHV)