Denver’s ATMU was conceived ahead of the 1991 Denver Grand Prix. Because of the configuration of the track, a large and densely populated area of downtown Denver would be inaccessible to ambulances during the race. In order to provide medical response to this area, paramedics aboard specially outfitted bicycles were deployed. The team's success was immediate. A 911 call for chest pain was initiated from a high-rise inside the perimeter. The ATMU was dispatched, and arrived at the building in 1-2 minutes. The team was able to quickly initiate advanced care for the patient, who was found to be having a heart attack. The patient was then transported over a bridge by golf cart to a waiting ambulance outside the perimeter.

Since then, the ATMU has expanded its role and capabilities. It is now deployed on an almost daily basis, anytime there are events that draw significant crowds. Each paramedic working with the ATMU is capable of working independently, and is equipped with an AED, oxygen, and a full complement of ALS supplies.