​​Post horns to sound on 17 July​

The post horn was invented in 1924 so that Postbuses on mountain postal routes could warn other road users and avoid collisions. Since then, the three-tone Du-Da-Do has become PostBus’s audio trademark and enjoys cult status. And this is what PostBus will be celebrating on Wednesday 17 July between 9.55 and 10 a.m. Within this time slot, drivers of ‘post horn Postbuses’ will sound their horns for around 30 seconds.

Of the 2,300 Postbuses, at least 700 are equipped with the three-tone horn, in addition to the standard horn. Drivers press their left foot on a pedal to make air flow from a compressed air tank to the horn, generating the 120-decibel three-tone horn, which sounds from the three bells on the underside of the vehicle.

Postbuses are equipped with three-tone horns for use on the steep sections of around 120 routes in mountainous areas. Graubünden has the densest Postbus network, followed by Wallis and Ticino. At the specified time on 17 July, the post horn will also be heard on other sections of these routes, for example in villages or at a bus stations. Passengers and passers-by are warmly invited to capture the initiative on their smartphones and to post on social media using the hashtag #Du-Da-Do.

Also to mark the post horn anniversary, PostBus has launched the creative competition ‘Do the Du-Da-Do’, which is running until 18 August 2024. A five-person jury will judge the submitted productions that use the three-tone horn as a motif. The award ceremony will take place in Bern at the end of September.

• On the afternoon of 17 July 2024, PostBus will publish impressions on social media of the initiative from German-speaking Switzerland, French-speaking Switzerland and Ticino.
• PostBus asks passengers and passers-by to please note that the post horn initiative on 17 July may be noisy – especially in covered bus stations. We recommend that you cover your ears.