As a stakeholder manager you usually know when work starts on site long before you know who it will affect. The schedule is fixed, and then the piecing together begins: which neighbourhoods and addresses does the closure affect, which business owners should be at the table first, which bus routes use that section, and where traffic will start rat-running through residential streets. The information exists, but it sits scattered across traffic models, address registers, timetables and separate reports. DHM and Argaleo built a solution that calculates the effect of a phasing plan on the surrounding area, entirely on open data. We are showing it on 8 October at the Landelijke Omgevingsmanagementdag, the Dutch national conference for stakeholder management.
The question keeps coming back
Every time the phasing changes, you start collecting it all again. And that is precisely the moment you need those conversations: with the municipality about the diversion route, with the bus operator about the stops, with the business owner about deliveries. The later that picture is complete, the less scope you have to adapt the phasing to it.
“As a stakeholder manager you want to know early on who and what a closure affects. That information is currently scattered across separate sources and reports, and with every change to the phasing you start all over again.”
Klaasje Braam, stakeholder manager at DHM
The case: major maintenance on the N231 Zuid
Our case is the major maintenance scheme on the N231 Zuid, between the Vrouwenakker bridge and the N196, due to be carried out in 2027 and 2028. It is an area with many growers and businesses sending lorries to Royal FloraHolland, a bridge that acts as a bottleneck, long diversions and bus routes run by two operators. The project team had specific questions: which section closes when, how much extra time the diversion adds for each mode of transport, who is affected by the closure, and which phasing variant puts least strain on the area. We chose the phasing in the example ourselves, so it differs from the project’s own programme.
From schedule to diversion to impact
You create the phases yourself: which sections are closed when, checked against the school holidays for the region. The model then calculates the quickest diversion for each phase, separately for cars, heavy lorries and e-bikes. Lorries get a route of their own, away from residential streets and roads with a width, weight or lorry restriction, and e-bikes are diverted via the cycle network. You can shape the diversion with route options such as avoiding village centres or the roads around schools, and the model recalculates immediately.
The third step shows what this means for the area: which bus routes use the closed section and how many minutes that adds per journey, which neighbourhoods and addresses face longer journeys to schools, GP surgeries, pharmacies or supermarkets, and where response times for the fire and ambulance services increase. Business premises are ranked by contact priority, so you can see who to speak to first. Planned works and events in the same period are flagged alongside, as are other projects running in the same area.
The fourth step puts two phasing variants side by side, for example closing everything at once compared with working in sections. Line by line you can see which variant puts least strain on the area, and you then record your preference and the reasoning behind it. The impact overview can be printed or saved as a PDF, so that municipalities, transport operators, emergency services and business owners all start from the same picture.
Open data as the foundation
Underneath it is information that is available for every project in the Netherlands: the road network with the characteristics of each section, including restrictions for lorries, addresses and buildings, residents per neighbourhood, schools with their pupil numbers, amenities and businesses, the public transport timetable, planned works and events, the school holiday dates for each region, and the output of the regional traffic model.
“Everything underneath is open data. The value lies in bringing it together around a single specific question from the stakeholder manager, and in being able to recalculate as soon as the phasing changes.”
Joost van der Ven, Product Owner Digitwin at Argaleo
The difference is one of order of magnitude. A conventional study of the surrounding area, with a calculation for each variant, takes weeks, and that work starts again with every change to the phasing. Here a new picture is ready within a day, roughly ten times faster. That is what changes the conversation about phasing: comparing variants suddenly fits within the time the project has.
The results are intended to inform the conversation, not to serve as a formal benchmark: the model uses assumptions about speeds, peak-hour distribution and capacity. This is about a way of working, and about what open data already makes possible. The solution was developed in Digitwin Labs, where Argaleo develops new applications with clients and partners before they become part of the Digitwin platform.
On show on 8 October
On Thursday 8 October 2026, Klaasje Braam (DHM) and Joost van der Ven (Argaleo) will present it in inspiration session 1.18, “From open data to usable insight into the surrounding area”. The session focuses on the substance: which stakeholders, mobility issues and neighbouring projects you recognise from your own projects, which open data you already use, and at what point in a project an up-to-date picture of the area is worth most. If you then want to see what it could do for a project of your own, come to the DHM stand (number 23), where the solution runs all day.
Your own project
The same questions come up with flood defence and dyke reinforcement, pipeline replacement and the renewal of bridges and viaducts: every scheme that involves phasing and diversions affects the area around it. We are happy to talk through what this would look like for your project, on 8 October or afterwards. Book an introductory meeting, or tell us what you are working on via the contact page.
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