PostAuto Switzerland, PostBus Ltd. (known as PostAuto Schweiz in Swiss Standard German (PostAuto AG), CarPostal Suisse in Swiss French (CarPostal S.A.), AutoPostale Svizzera in Swiss Italian (AutoPostale S.A.), and AutoDaPosta Svizra in Romansh (AutoDaPosta S.A.) is a subsidiary company of the Swiss Post, which provides regional and rural bus services throughout Switzerland, and also in France, Germany, and Liechtenstein.
The Swiss PostAuto service evolved as a motorized successor to the stagecoaches that previously carried passengers and mail in Switzerland, with the Swiss postal service providing postbus services carrying both passengers and mail. Although this combination had been self-evident in the past, the needs of each diverged towards the end of the twentieth century, when the conveyance of parcels was progressively separated from public transportation. This split became official with the conversion of PostAuto into a separate subsidiary of the Swiss Post in February 2005.
The buses operated by PostAuto are a Swiss icon, with a distinctive yellow livery and three-tone horn. The company uses an image of a posthorn as a logo on its buses and elsewhere. On some mountain roads, indicated by a traffic sign of a yellow posthorn on a blue background, the public transport, in particular the postal buses, have priority over other traffic and traffic users must follow instructions by public transport drivers.