Aerobus is a self-propelled electrically powered bus-like vehicle riding on a suspended overhead cable. The cable arrangement, similar to a suspension bridge, allows for long spans of up to 600 metres between pylons. The Aerobus system was invented in the late 1960s by Gerhard Mueller of the GMD Mueller aerial lift company in Switzerland. The patents to Aerobus are currently owned by Aerobus International Ltd. of Houston, Texas, United States.