An ambulance is a vehicle for transportation of sick or injured people to, from or between places of treatment for an illness or injury, and in some instances will also provide out of hospital medical care to the patient. The word is often associated with road going emergency ambulances which form part of an emergency medical service, administering emergency care to those with acute medical problems.
The term ambulance does, however, extend to a wider range of vehicles other than those with flashing warning lights and sirens. The term also includes a large number of non-urgent ambulances which are for transport of patients without an urgent acute condition (see below: Functional types) and a wide range of urgent and non-urgent vehicles including trucks, vans, bicycles, motorbikes, station wagons, buses, helicopters, fixed-wing aircraft, boats, and even hospital ships (see below: Vehicle types).
Ambulances can be grouped into types depending on whether or not they transport patients, and under what conditions. In some cases, ambulances may fulfil more than one function (such as combining emergency ambulance care with patient transport).
- Emergency ambulance – The most common type of ambulance, which provide care to patients with an acute illness or injury. These can be road-going vans, boats, helicopters, fixed-wing aircraft (known as air ambulances) or even converted vehicles such as golf carts.
- Patient transport ambulance – A vehicle, which has the job of transporting patients to, from or between places of medical treatment, such as hospital or dialysis center, for non-urgent care. These can be vans, buses or other vehicles.
- Response unit – Also known as a fly-car or a [Quick Response Vehicle], which is a vehicle which is used to reach an acutely ill patient quickly, and provide on scene care, but lacks the capacity to transport the patient from the scene. Response units may be backed up by an emergency ambulance which can transport the patient, or may deal with the problem on scene, with no requirement for a transport ambulance. These can be a wide variety of vehicles, from standard cars, to modified vans, motorcycles, pedal cycles, quad bikes or horses. These units can function as a vehicle for officers or supervisors (similar to a fire chief's vehicle, but for ambulance services). Fire & Rescue services in North America often staff EMTs or Paramedics to their apparatuses to provide medical care without the need to wait for an ambulance.
- Charity ambulance – A special type of patient transport ambulance is provided by a charity for the purpose of taking sick children or adults on trips or vacations away from hospitals, hospices or care homes where they are in long term care. Examples include the United Kingdom's 'Jumbulance' project. These are usually based on a bus.
- Bariatric ambulance – A special type of patient transport ambulance designed for extremely obese patients equipped with the appropriate tools to move and manage these patients.
Ambulance design must take into account local conditions and infrastructure. Maintained roads are necessary for road going ambulances to arrive on scene and then transport the patient to a hospital, though in rugged areas four-wheel drive or all-terrain vehicles can be used. Fuel must be available and service facilities are necessary to maintain the vehicle.
