Summary

The Federal Roads Office (ASTRA) expects significant traffic volume on Swiss national highways during the extended weekends for Ascension Day (May 14–17), Whitsunday (May 22–25), and Corpus Christi (June 4–7) 2026. The north-south axes A2 Gotthard and A13 San Bernardino are particularly at risk of congestion. ASTRA recommends travelers to remain on the motorway and avoid diverting traffic to secondary roads. Several construction site regulations will be adjusted over the holidays: the Kerenzerberg tunnel will remain open continuously during Ascension Day and Whitsunday, the one-lane restriction on the A9 Simplon Pass will be lifted, and the bicycle shuttle on the Axen Road will operate on the summer schedule.

People

Topics

  • Traffic safety and congestion management
  • Alpine transit and alternative routes
  • Construction site coordination during holiday periods
  • Public traffic information

Clarus Lead

ASTRA's warning against diverting traffic addresses a structural problem: congestion on main routes shifts traffic to local roads in mountain villages, which increases accident risks and disrupts economic activity. This forecast comes in a year of increased transit burden, as the Gotthard Pass is opening in the coming days and travelers must choose between multiple alternative routes. The coordinated opening of tunnels and construction site releases over the holidays demonstrates how closely infrastructure management and traffic control are interlinked.

Detailed Summary

ASTRA expects peak traffic particularly on the A2 Gotthard and A13 San Bernardino, the two main transit axes heading south. In addition to these core routes, agglomerations (Zurich, Basel, Bern, Lucerne, Lausanne, Geneva) on the A1, A2, and A3 are chronically overloaded. To relieve congestion, alternative routes are available: the Great St. Bernard Tunnel, Simplon Pass, and Lötschberg/Simplon car shuttle. The Gotthard Pass will be released as an additional alternative.

Specific construction measures will characterize the traffic situation: on the A4 Axen Road between Kandersteg and the Kandersteg loading station, only one lane is passable due to bridge work; traffic lights are synchronized with loading train departure times, and waiting times are possible. On the A9 Simplon Pass, the one-lane restriction at Casermetta will be lifted over the holidays. The A3 Kerenzerberg tunnel will be open continuously during Ascension Day (May 13–18) and Whitsunday (May 22–26); on other days regular night closures occur with counter-traffic via the lake route. On Corpus Christi (June 4), the tunnel remains completely closed. The bicycle shuttle on the Axen Road has been operating on the summer schedule since April 1 (06:25–20:50 hourly).

Key Points

  • Travelers should remain on motorways during congestion and not divert to secondary roads to relieve villages and reduce accident risks.
  • Multiple Alpine passes and tunnels will open or be released; travelers should check current opening status before departure (TCS Pass Portal).
  • Construction site regulations will be made more flexible over holidays (Kerenzerberg tunnel open, Simplon Pass one lane free) to optimize traffic flow.

Critical Questions

  1. Evidence/Data Quality: Is the forecast of "high traffic volume" based on historical data from previous holidays or on real-time models? What are the error margins of the prediction?

  2. Conflicts of Interest: Which cantons benefit or lose from the recommendation to avoid diverting traffic – particularly cantons with mountain villages on the A4 and A13?

  3. Causality: Is it proven that diverted traffic on municipal roads leads to more accidents than steady traffic on main routes, or is this an assumption?

  4. Feasibility: How is compliance with the recommendation monitored? Are there steering measures (toll systems, driving bans) or only appeals?

  5. Alternative Hypotheses: Could opening the Gotthard Pass (instead of only tunnels) reduce traffic on main routes rather than concentrate it?

  6. Side Effects: Do longer travel times due to congestion lead to increased fuel consumption and CO₂ emissions compared to alternative routes?

Source Directory

Primary Source: Spring Holidays 2026: ASTRA Warns of Traffic Chaos – news.admin.ch, 04.05.2026

Supplementary Sources:

  1. BLS Car Shuttle – www.bls.ch/de/fahren/autoverlad
  2. A9 Simplon – www.a9-simplon.ch/simplon/de/arbeiten-2026/uebersicht
  3. Kerenzerberg Tunnel – kerenzerbergtunnel.ch
  4. TCS Pass Portal – www.tcs.ch/de/tools/verkehrsinfo-verkehrslage/paesse-in-der-schweiz.php

Verification Status: ✓ 04.05.2026

This text was created with the support of an AI model. Editorial Responsibility: clarus.news | Fact-Check: 04.05.2026