Multiple realities
(covers information from several alternate timelines)
A 1940s ambulance in 1953
An ambulance was an automobile used on Earth to transport the sick or injured. Ambulance attendants were known as paramedics.
In 1953, Benny Russell was placed in a 1940s Chevrolet ambulance outside the offices of the magazine Incredible Tales of Scientific Wonder. (DS9: "Far Beyond the Stars")
In 2259 of the alternate reality, an ambulance that was either an aircar or shuttle was parked at the Royal Children's Hospital. (Star Trek Into Darkness)