Accurate and up-to-date speed limit information is essential for reliable navigation, digital traffic services and road safety. However, maintaining consistent digital records across extensive road networks remains a challenge for road authorities and national data organisations. A pilot project in the Netherlands, conducted within the TISGRADE initiative, demonstrates how targeted data quality checks and cooperation between local and national stakeholders can help address this problem.

The Dutch National Data Warehouse for Traffic Information (NDW) compared speed limit information from its road network database with data available in OpenStreetMap (OSM). The comparison revealed considerable discrepancies across local road networks, indicating the need for more systematic validation.

Based on the results, NDW launched a pilot involving ten municipalities where discrepancies exceeded 7%. With explicit permission from the participating municipalities, NDW investigated and corrected speed limit information on their behalf using the George application – a platform that enables road operators to view and modify geographical data and road characteristics.

The validation process combined several information sources, including recent street-level imagery, traffic sign datasets, local asset management systems and existing traffic data. By comparing these sources, the project team could identify inconsistencies and determine where corrections were necessary.

Initial results showed a substantial reduction in the proportion of speed limits differing from the reference data in the participating areas. The pilot also contributed to a decrease in the average discrepancy rate across the national dataset.

An important finding concerns the division of responsibilities. Local road authorities possess detailed knowledge of their infrastructure, traffic conditions and regulatory decisions, while national data organisations can provide large-scale analysis, access to multiple datasets and expertise in data processing. Combining these capabilities allows straightforward inconsistencies to be addressed centrally, while more complex cases can be referred to local authorities for verification.

The approach is now being further refined to make data quality improvements more efficient and sustainable.
The experience is relevant beyond the Netherlands. As European requirements for Real-Time Traffic Information (RTTI) increase the demand for reliable and accessible traffic data, the pilot offers a practical example of how national coordination and local expertise can work together. Better speed limit data can ultimately support more accurate navigation services, safer journeys and more consistent traffic information across Europe.

The whole article you can find here.

TISGRADE. Improving Speed Limit Data: Combining Local Knowledge with National Expertise [online]. 20 October 2026 [cited 2026-10-26]. Available from: https://www.tisgrade.eu/latest/news/2026/10/20/improving-speed-limit-data-combining-local-knowledge-with-national-expertise

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