ZoneScope30

Automated identification and visualization of 30 km/h (Tempo 30 / 20 mph) zones based on OpenStreetMap (OSM) data and PostGIS analysis. A Node.js proxy is included to bypass CORS restrictions between the browser and GeoServer.

License

Source Code: This project’s source code (scripts, SQL, proxy, and frontend) is licensed under the MIT License.

Data: This project uses OpenStreetMap data © OpenStreetMap contributors.The data is licensed under the Open Database License (ODbL) 1.0.https://www.openstreetmap.org/copyright

Basemap: Satellite imagery is provided by Esri World Imagery and is used for visualization purposes only.

Core components

This project integrates several tools for importing, analyzing, and serving geospatial data:

Component	Layer	Purpose
osm2pgsql	Data	Imports OSM data into PostgreSQL.
PostGIS	Data	Stores OSM geometries and performs spatial analysis.
GeoServer	Service	Exposes analysis results as a WFS.
Express.js	Service	Provides a CORS-bypassing proxy for WFS requests.
MapLibre	Presentation	Displays the identified Tempo-30 segments on a web map.

Overview of the workflow

1. Select eligible roads: Only primary, secondary, tertiary, and residential roads not already tagged as 30 km/h zones are considered; living streets are excluded.
2. Buffer trigger objects: Social facilities, schools, care facilities, playgrounds, and zebra crossings are buffered by 50 m; residential buildings by 5 m (noise protection applies only to primary roads).
3. Identify affected road segments: Roads intersecting the buffered objects are flagged as candidates.
4. Extend zones: Segments are buffered by 150 m to ensure minimum 300 m zone length.
5. Close gaps: Morphological operations fill gaps smaller than 500 m.
6. Finalize selection: Only segments with the same name or within 1 m of a candidate are retained to ensure that unrelated roads are excluded.

Installation and setup

1. Install OSGeoLive 16.0 as a virtual machine

2. Clone this repo

git clone https://github.com/HKA-OSGIS/ZoneScope30

3. Initialize setup

Navigate in the repo folder and run the setup script to install all dependencies:

cd ZoneScope30

bash setup.sh

4. Start application

Navigate in the repo folder and run the start.sh to start the application:

bash start.sh

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Tempo 30 zone logic

The classification of road segments follows a multi-stage spatial logic based directly on OSM tagging and neighborhood analysis.

1. Eligible roads

Only roads meeting all of the following criteria are evaluated:

• Road class in: highway=primary, highway=secondary, and highway=tertiary.
• Not a living street: highway!=living_street
• No existing valid 30-zone tagging. Ignored cases include:
  • Numeric maxspeed > 30
  • Non-numeric maxspeed not in: DE:zone:30

2. Primary zone identification

A road segment becomes a Tempo 30 candidate if at least one of the following applies:

A. Automatic assignment

• Residential roads: All highway=residential segments are automatically classified as Tempo 30.

B. Social facilities (protective zones)

Applies to highway=primary, highway=secondary, and highway=tertiary.

A segment qualifies if it lies within 50 m of one or more of the following:

• Schools: amenity=school
• Kindergartens: amenity=kindergarten, amenity=childcare
• Senior & care facilities: nursing_home, hospital, social_facility with social_facility:for=senior
• Playgrounds: leisure=playground
• Pedestrian crossings: highway=crossing with crossing=zebra or crossing_ref=zebra

C. Noise protection (residential exposure)

Applies to highway=primary only.

A segment qualifies if it lies within 5 m of residential buildings:

• building=residential
• building=apartments
• building=house
• building=terrace

3. Zone extension (network consistency)

After primary segments are determined, zones are extended for consistency:

• Protected zone length: Identified segments are treated as 300 m protected corridors.

• Gap filling: If two Tempo-30 corridors are less than 500 m apart, the intermediate road segment is also classified as Tempo 30.

This produces continuous, real-world-aligned Tempo-30 areas instead of isolated fragments.

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Architecture