Its capacity to transport 123 people and its overall length of 20.03 metres have secured the largest ambulance in the world – a large-capacity emergency ambulance based on the Mercedes-Benz Citaro articulated bus – a place in the Guinness Book of Records.

On Friday, 25 September 2009, an extraordinary record attempt took place in front of the Rhineland-Palatinate State Parliament in Mainz, Germany. Representatives from the Centre of Ambulance Services of the Government of Dubai, present at the event for the official hand-over of the bus, along with countless onlookers and a large media contingent, were in attendance as the official Guinness World Records judges, the Rhineland-Palatinate Interior Minister Karl Peter Bruch and Joachim Mertes, President of the Parliament of Rhineland-Palatinate, measured the precise transport capacity of the Citaro.

The entry in the Guinness Book of records is registered in the name of the companies that designed, built and equipped the bus: Von Bergh Global Medical Consulting, Gebr. Heymann GmbH, Cytomed Middle East and EvoBus GmbH. Aid workers from the German Red Cross, the St. John's Ambulance organisation and the ASB, the Worker's Samaritan Association of Germany simulated a mass casualty event in which numerous accident victims needed to receive medical treatment simultaneously.

This simulation revealed that the large-capacity emergency ambulance is capable of treating and transporting up to 123 people. The variant of the articulated bus which broke the world record has an overall length of 20.03 metres (including a rear-mounted medical-supplies box) and is the third Mercedes-Benz large-capacity emergency ambulance to be delivered to Dubai. Two standard buses measuring 12 metres in length and one articulated bus measuring 18 metres in length are used as large-capacity emergency ambulances in Dubai. Bus variant A is designed as a mobile intensive-care unit, while variant B features equipment for the large-scale treatment and transport of medium and less severely injured accident victims. Bus variant C is a combination of variants A and B.

The three Mercedes-Benz clinic buses were ordered so that rapid medical assistance can be provided in the event of major incidents, i.e. accidents or disasters involving large numbers of injury victims. After all, the survival chances of very seriously injured people depend largely on them receiving rapid first-aid treatment. While a two-man crew is normally only able to care for one patient in an ambulance, up to 20 patients can receive care from four medical specialists in the Mercedes-Benz large-capacity emergency ambulance. The vehicles were produced by conversion specialist Gebrüder Heymann GmbH, based on the concept and design provided by international research and consultancy company Von Bergh Global Medical Consulting, which was also responsible for project management.

The entry in the Guinness Book of Records is the latest chapter in the Mercedes Benz Citaro success story. On 8 September the 25,000th Citaro was delivered to infra fürth verkehr gmbh, thus making the Citaro the most successful urban bus of all time.