National roads overloaded in 2025 despite improvements

The national roads are the backbone of mobility in Switzerland. They relieve villages and urban areas and open up regions for goods and people. Although they account for only about three percent of the entire road network, nearly 45 percent of all vehicle kilometers were traveled on them in 2025 – a total of around 30 billion kilometers. With 68,040 hours of traffic jams, congestion increased significantly compared to the previous year. This shows that despite targeted measures to improve traffic flow, the national road network is increasingly reaching its capacity limits.

In 2025, approximately 30 billion vehicle kilometers were traveled on the national road network (+1.4 percent compared to 2024). About 25 billion kilometers were accounted for by passenger cars (+1.5 percent). The freight traffic is also heavily reliant on the national roads: More than 70 percent of road-based heavy freight traffic was handled via the national road network. This is evident from the report „Traffic Development and Availability of the National Road 2025.“

Network Reaches Capacity Limits

In 2025, a total of 68,040 hours of traffic jams were recorded – an increase of about 20 percent compared to the previous year. Approximately 89 percent of the traffic jams are due to traffic congestion, while less than 4 percent are attributed to construction sites, which is below the previous year’s figure. Routes with heavy commuter traffic were particularly affected, namely the A1 Geneva – St. Gallen, A2 Basel – Chiasso, and A3 Basel – Sargans. The hours of congestion at the Gotthard Tunnel were roughly at the same level as in 2024.

The significant increase in traffic jam hours indicates that congestion on the national road network is not occurring in isolated spots. There are increasingly recurring, structural bottlenecks on important sections. At the same time, traffic is spreading more evenly throughout the day, especially in the central region. As a result, the network is not only heavily burdened during morning and evening peak times but is nearly permanently congested in many areas. Even minor incidents such as breakdowns or accidents can lead to traffic jams and slow-moving traffic. Travel times on the national roads are becoming increasingly unpredictable. This may contribute to road users avoiding the national roads and increasingly diverting to cantonal and municipal roads.

This is particularly evident on the main axes A1 and A2. On many cantonal roads, traffic growth is higher than on the parallel highways. This is a sign that road users are increasingly conducting their trips via the downstream road network and less via the national roads.

Intelligent Traffic Management Systems Show Effect

The ASTRA is addressing this development with various measures to improve traffic flow. Intelligent traffic management systems such as speed harmonization or the temporary opening of the emergency lane help to utilize the existing infrastructure more efficiently. For example, on the A6 between Thun and Bern and on the A1 near Winterthur, traffic jams were significantly reduced through the use of emergency lanes. Additionally, ASTRA is centralizing the control of these systems more across Switzerland and continuously improving the control algorithms. The application developed for this purpose, „Traffic Management Switzerland,“ has been operational for the first traffic management installations since the end of 2025. In parallel, ASTRA, together with the automotive industry, is consistently pursuing the potentials of highly assisted and automated driving. These efforts will have a positive impact on traffic flow and traffic safety in the medium and long term.

Targeted Expansions Provide Long-Term Relief

Traffic management and automated driving alone are not sufficient to ensure the long-term functionality of the network. Systematic bottlenecks threaten the overall network function. To address this challenge, targeted expansions are advisable. As part of the project „Traffic ’45“, the UVEK has prioritized planned expansion projects for roads and railways and developed a proposal for the targeted further development of the national roads. The goal remains to secure the long-term availability of the network, relieve cantonal and municipal roads, and maintain the performance of the national roads even during construction or events. The Federal Council opened the consultation on the proposal on June 19, 2026.

Collection of Traffic Jam Hours

The traffic jam hours are based on traffic reports from Viasuisse. For each traffic jam event, the start and end are recorded and statistically evaluated. It is ensured that each traffic jam is counted only once and is clearly assigned to a national road.

ASTRA is continuously developing traffic jam detection. In the future, traffic jam hours could increasingly be recorded automatically, for example, using Floating Car Data or traffic modeling. It remains important that the methodology and data basis remain stable and traceable in the long term, so that comparisons over several years are possible.

Traffic Flow Report