Accessibility analysis for municipalities

Having services is not the same as reaching them

A municipality can count how many GP practices, nurseries or supermarkets each district has. That number does not say how long it takes to get there. A district with four playgrounds can be worse served than a district with two, if the four sit at one edge and the two sit in the middle. And a nursery five minutes away does not help a family if every place is taken.

The difference is clearest when facilities close. In Saarland, more than 30 per cent of maternity wards have closed since 2014. We used GOAT to see what that means for journeys. Over 200,000 people, more than 20 per cent of the population, now need more than 30 minutes by car to reach the nearest maternity ward. By public transport, more than 65 per cent need over 40 minutes.

Municipalities, districts and planning offices face very practical questions. Which parts of town have no GP within reach without a car? Where is a link missing in the walking or cycling network? Where would a new stop or a new nursery make the most difference? These questions are part of mobility plans, in plans for walking and cycling at neighbourhood level, in healthcare planning and in every choice of site. An accessibility analysis answers them for every part of the area, not as one average for the whole municipality.

How an accessibility analysis works

An accessibility analysis combines three things: where people live, where the destinations are, and how long it takes to travel between them. For a short definition, see our glossary. This page is about how we do it.

It starts with four choices: which destinations count, by which mode, within what time, and for whom. A threshold of 15 minutes and one of 30 minutes give two different maps of the same region, and both can be justified. So the values you chose belong in every result.

Which method fits depends on the question. The simplest is the catchment area. An isochrone shows how far you can get from a facility in a given time, along the real street network, and how many people live inside it. Heatmaps rate every cell of a grid instead, for example by the average travel time to the nearest destinations, or by how many attractive destinations are nearby. Where capacity is limited, such as in childcare or doctors’ practices, 2SFCA compares supply with demand. For public transport, it also matters how often a bus or train runs, and that is what public transport quality classes measure. Our guide to GOAT’s eight accessibility tools shows when to use which, on one example from Bonn.

The result is a map of service gaps: the places that fail the test you defined. Add population data and you also know how many people live there.

An accessibility analysis measures how long a journey takes, not how good it is. Whether a pavement is wide enough, lit and step-free is often missing from standard network data. In Augsburg, we added this through a site survey, including street lighting, crossings and barriers, and used it to calculate a walkability index.

Accessibility analysis in GOAT

In GOAT, the tools are under Accessibility Indicators. With Catchment Area you calculate isochrones by time or distance, for Walk, Bicycle, Pedelec, Car and Public Transport. The heatmaps, among them Heatmap - Closest Average, Heatmap - Gravity and Heatmap 2SFCA, rate the whole area on a grid. For public transport there are also ÖV-Güteklassen and Trip Count Platform. The GOAT documentation explains each setting of the catchment area tool.

The routing networks for walking, cycling and driving cover more than 30 European countries. Public transport covers Germany, Switzerland and the Haut-Rhin region in France. You add destinations, population and administrative boundaries to your project from the data catalog, or upload your own data, such as the childcare places in your town. Save the steps as a workflow and run it again when the data changes.

We use the same tools in our projects. In Sinsheim, we assessed the walking, cycling and public transport networks for the whole town and combined them with origin and destination data from mobile phones. For the Munich district of Allach-Untermenzing, we are working with Sweco on access on foot, by bike and by public transport, together with site visits and public participation. For the MOBITAT project, we calculated for all 520 municipalities of the Frankfurt Rhine-Main region what share of the population reaches everyday destinations by bike and by public transport within 5, 10, 15, 20 or 25 minutes. In the district of Südliche Weinstraße, we looked at how visitors reach tourist destinations by bus and train, including the VRNflexline on-demand service.

You can run the analysis yourself in GOAT, or ask us to do it for your area. The projects are listed directly below.