ambulance

The Star of Life, a symbol used on ambulances to denote the 6 stages of pre-hospital care

An ambulance in San Jose del Cabo, Mexico

A Helicopter used as an Ambulance

A boat ambulance in Venice

Response Unit - Czech Republic

An ambulance is a vehicle for transporting sick or injured people,^[1]to, from or between places of treatment for an illness or injury. The term ambulance is used to describe a vehicle used to bring medical care to patients outside of the hospital and when appropriate, to transport the patient to hospital for follow-up care and further testing. In some jurisdictions there is a modified form of the ambulance used, that only carries one member of ambulance crew to the scene to provide care, but is not used to transport the patient.^[2] In these cases a patient who requires transportation to hospital will require a patient-carrying ambulance to attend in addition to the fast responder.

The term ambulance comes from the Latin word ambulare, meaning to walk or move about ^[3] which is a reference to early medical care where patients were moved by lifting or wheeling. The word is most commonly associated with the land-based, emergency motor vehicles that administer emergency care to those with acute illnesses or injuries, hereafter known as emergency ambulances. These are usually fitted with flashing warning lights and sirens to facilitate their movement through traffic. It is these emergency ambulances that are most likely to display the Star of Life,^[4] shown on the right, which represents the six stages of prehospital medical care.

There are other types of ambulance, with the most common being the patient transport ambulance. These vehicles are not usually (although there are exceptions) equipped with life-support equipment, and are usually crewed by staff with fewer qualifications than the crew of emergency ambulances. Their purpose is simply to transport patients to, from or between places of treatment. In most countries, these are not equipped with flashing lights or sirens.

Other vehicles used as ambulances include trucks, vans, station wagons, buses, helicopters, fixed-wing aircraft, boats, and even hospital ships.

Functional types

Ambulances can be grouped into types depending on whether or not they transport patients, and under what conditions:

1. 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, helicopters, fixed-wing aircraft (known as air ambulances) or even converted vehicles such as golf carts.
2. 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.
3. Response Unit - Also known as a fly-car, 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).
4. 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.^[5] These are usually based on a bus.

Vehicle types

Ambulances can be based on many types of vehicle, although emergency and disaster conditions may lead to other vehicles serving as makeshift ambulances:

1. Van - A typical ambulance is of a van construction, based on a standard chassis, usually with a maximum road weight loaded of between 3.5 and 7.5 tonnes. In North America, the large box type vehicles are referred to as "mods" (modular) and the smaller van type vehicle is often called a "high-top".
2. Car/SUV - Used either as a fly-car for rapid response^[2] or for patients who can sit, these are standard car models adapted to the requirements of the service using them. Some cars are capable of taking a stretcher with a recumbent patient, but this often requires the removal of the front passenger seat, or the use of a particularly long car. This was often the case with early ambulances, which were converted (or even serving) hearses, as these were some of the few vehicles able to accept a human body in a supine position).
3. Motorcycle - In developed areas, these are used for rapid response in an emergency^[6] as they can travel through heavy traffic much faster than a car or van, although in the developing world, trailer or sidecar adaptations make these patient transporting units.^[7][8]
4. Bicycle - Used for response, but usually in pedestrian only areas where large vehicles find access difficult.^[9][10] Like the motorcycle, a bicycle may be connected to a trailer for patient transport, most often in the developing world.^[11]
5. All Terrain Vehicle - Such as a 'quad bike', these are used for response off road,^[12] especially at events. ATVs can be modified to carry a stretcher, and are used for tasks such as mountain rescue in inaccessible areas.
6. Golf cart - Used for rapid response at events.^[13] Function similar to ATVs, with less rough terrain capability, but with less noise.
7. Helicopter - Usually used for emergency care, either in places inaccessible by road, or in areas where speed is of the essence, as they are able to travel significantly faster than a road ambulance.^[14]
8. Fixed-wing aircraft - These can be used for either acute emergency care in remote areas (such as in Australia, with their 'Flying Doctors'^[15]) or for patient transport over long distances (usually a re-patriation following an illness or injury in a foreign country.^[16][17])
9. Boat - Boats can be used to serve as ambulances, especially in island areas.^[18] Some lifeboats or lifeguard vessels may fit the description of an ambulance as they are used to transport a casualty.
10. Ship – Ships can be used as hospital ships, mostly operated by national military services,^[19] although some ships are operated by charities.^[20] This can meet the definition of ambulances as they provide transport to the sick and wounded (along with treatment). These are often send to disaster or war zones to provide care for the casualties of these events.

History

Early patient transport

There is evidence of forced transport of those with psychiatric problems or leprosy in to ancient times.^[21] The first record of an ambulance was probably a hammock based cart constructed around 900AD by the Anglo-Saxons.

During the Crusades of the 11th Century, the Knights of St John set up hospitals to treated pilgrims wounded in their battles in the 'holy land', although there is no clear evidence to suggest how the wounded made their way to these hospitals.

In Norman times, a litter suspended between horses on two poles was used.^[21] Variations on the horse litter and horse drawn wagons were used from then right up to the 20th century.

Early battlefield treatment

The first record of ambulances being used for emergency purposes was the use by Queen Isabella of Spain, in 1487. The Spanish army of the time was treated extremely well and attracted volunteers from across the continent, and part of this was the first military hospitals or 'ambulancias', although injured soldiers were not picked up for treatment until after the cessation of the battle, resulting in many dying on the field.

A major change in usage of ambulances in battle came about with the ambulance volantes designed by Dominique Jean Larrey (1766–1842), Napoleon Bonaparte’s chief physician. Larrey was present at the battle of Spires, between the French and Prussians, and was distressed by the fact that wounded soldiers were not picked up by the numerous ambulances (which Napoleon required to be stationed two and half miles back from the scene of battle) until after hostilities has ceased, and set about developing a new ambulance system.^[21] Having decided against using the Norman system of horse litters, he settled on two or four-wheeled horse drawn wagons were used to transport fallen soldiers from the (active) battlefield after they had received early treatment in the field. These 'flying ambulances' were first used by Napoleons Army of the Rhine is 1793. Larrey subsequently developed similar services for Napoleon's other armies, and adapted his ambulances to the conditions, including developing a litter which could be carried by a camel for a campaign in Egypt.

Development of civilian services

In civilian ambulances, a major advance was made with the introduction of a transport carriage for cholera patients in London in 1832. The Times newspaper said that "The curative process commences the instant the patient is put in to the carriage; time is saved which can be given to the care of the patient; the patient may be driven to the hospital so speedily that the hospitals may be less numerous and located at greater distances from each other".^[21].

A horse drawn ambulance from the American Civil War (1861-1865)

Advances during the American Civil War

More advances in medical care for the military were made during the United States’ Civil War. Union military physicians Joseph Barnes and Jonathan Letterman built upon Larrey’s work and designed a prehospital care system for soldiers, which used new techniques and methods of transport. They ensured that every regiment possessed at least one ambulance cart, with a two wheel design that accommodated two or three patients. These ambulances unfortunately proved to be too lightweight for the task, and were phased out to be replaced by the "Rucker" ambulance, named for Major General Rucker,^[21] which was a four wheeled design, and was a common sight on battlefield of that war. Other vehicles were pressed in to service during the civil war, including a number of Steamboats, which served as mobile hospitals for the troops. It was in this period that the practice of transporting wounded soldiers to treatment facilities by railroad was introduced.^[22]

Hospital based services begin

A horse-drawn ambulance outside Bellevue Hospital in New York City, 1895

The first known hospital based ambulance service was based out of Commercial Hospital, Cincinnati, Ohio (now the Cincinnati General) by 1865.^[21] This was soon followed by other services, notably the New York service provided out of Bellevue Hospital.

Edward Dalton, a former surgeon in the Union Army, was charged with creating a hospital in lower New York, he started an ambulance service to bring the patients to the hospital faster and in more comfort, which started in 1869. He claimed the service was the first of its kind, being unaware of the work in Cincinnati four year earlier. These ambulances carried medical equipment, such as splints, a stomach pump, morphine, and brandy, reflecting contemporary medicine. Dalton believed that speed was of the essence, and horses were left harnessed, being attached to the ambulance by a 'drop' or 'snap' harness, meaning they were ready to go within 30 seconds of being called. The scene was very popular, and its fame spread — During the year 1870, the ambulances attended 1401 emergency calls, but twenty one years later, this had more than tripled to 4392.^[21] By the turn of the century, interns accompanied New York City ambulances, treated patients on scene, and often left them at home.^[22]

In 1867, the city of London's Metropolitan Asylums Board, in the United Kingdom, received six horse-drawn ambulances for the purpose of conveying smallpox and fever patients from their homes to a hospital. These ambulances were designed to resemble private carriages, but were equipped with rollers in their floors and large rear doors to allow for a patient, lying on a specially designed bed, to be easily loaded. Space was provided for an attendant to ride with the patient, and the entire patient compartment was designed to be easily cleaned and decontaminated. Anyone willing to pay the cost of horse hire could summon the ambulance by telegram or in person.^[23]

Dedicated services begin

In June 1887 the St John Ambulance Brigade was established to provide first aid and ambulance services at public events in London.^[24] It was modeled on a military-style command and discipline structure. The St John Ambulance Association had already been teaching first aid to the public for 10 years prior to that.^[24] National or state based branches of St John Ambulance now provides ambulance and first aid services in many countries around the world. ^[25]

In Queensland, a state in Australia, military medic Seymour Warrian called a public meeting in Brisbane and established an ambulance service after witnessing an event at the Brisbane showgrounds during Show Week in 1892.^[26] A fallen rider, suffering a broken leg was walked off the field by well meaning but misguided bystanders, worsening his injury. As a result of the meeting, the Queensland Ambulance Transport Brigade was formed on the 12th September.^[26] The first ambulance station in Queensland operated out of the Brisbane Newspaper Company and officers on night duty slept on rolls of newspaper on the floor. They had a stretcher, but no vehicle and transported patients on foot, although in time, they gained horse drawn stretchers and eventually vehicles. A year after the establishment of the Brisbane centre, another was established in Charters Towers in north Queensland, growing to over 90 community controlled ambulance centres. In 1991 the independent QATB centres amalgamated to form the Queensland Ambulance Service which is now the fourth largest ambulance service in the world.^[26]

Mass transit use for emergency medical provision

In the late 19th century cities, including Bahia, Brazil and St Louis, Missouri, United States started using trolley cars on their tram network which were designed to act as ambulances, transporting the sick and injured. The trolley cars in Bahia included a fumigating compartment and a two bed nurses work area. The design of the tram network in St Louis was such that the ambulance streetcar, introduced in 1894 was able to reach all 16 infirmaries in the city.^[21]

In Germany, in 1902, a civilian ambulance train was introduced (building on the use of trains during military conflict) for use during railway accidents. It housed a mobile operating room and eight stretchers. Railroad employed surgeons lived near the railway station where the ambulance train was stationed, and were summoned to urgently attend in the event of an emergency. The train had priority over the tracks, with all other trains obliged to give way.^[21]

Introduction of motor units

A 1948 Cadillac A. J. Miller ambulance. The A. J. Miller company purchased this car from Cadillac, then modified it to turn it into an ambulance. The resemblance to a hearse is obvious. (see text)

In the late 19th century, the automobile was being developed, and started to be introduced alongside horse-drawn models, early 20th century ambulances were powered by steam, gasoline, and electricity, reflecting the competing automotive technologies then in existence. However, the first motor powered ambulance was brought in to service in the last year of the 19th century, with the Michael Reese Hospital, Chicago, taking delivery of the first automobile ambulance, donated by 500 prominent local businessmen, in February 1899.^[21] This was followed in 1900, by New York city, who extolled its virtues of greater speed, more safety for the patient, faster stopping and a smoother ride. These first two automobile ambulances were electrically powered with 2 horse power motors on the rear axle.^[21]

The first gasoline powered ambulance was the Palliser Ambulance, introduced in 1905, and named for Major Palliser of the Canadian Militia. This three wheeled vehicle (one at the front, two at the rear) was designed for use on the battlefield, under enemy fire. It was a heavy tractor unit, cased in bullet proof steel sheets. These steel shields opened outwards to provide a small area of cover from fire (nine feet wide by 7 feet high) for the ambulance staff when the vehicle was stationary.^[21]

The British Army was quickly behind the Canadians in introducing a limited number of automobile ambulances. In 1905, the Royal Army Medical Corps commissioned a number of Straker-Squire motor ambulance vans. They were based on a double decker bus manufactured by the same company, although on a shorter wheel base.^[27] A number of them were based in Oxfordshire, serving several major encampments in the area.^[21]

The first mass production automobile based ambulance (rather than one off models) was produced in the United States by the James Cunningham, Son & Company of Rochester, New York, a manufacturer of carriages and hearses, in 1909. This ambulance was named the Model 774 Automobile Ambulance. The ambulance featured a proprietary 32 horsepower, 4 cylinder internal combustion engine. The chassis rode on pneumatic tires, while the body featured electric lights, a suspended cot with two attendant seats, and a side mounted gong. ^[28]

World War One

Ford 1916 Model T Field Ambulance. This canvas on wood frame model was used extensively by the British & French as well as the American Expeditionary Force in World War I. Its top speed was 45mph produced by a 4 cylinder water cooled engine.

During World War One, the Red Cross brought in the first widespread battlefield motor ambulances to replace horse drawn vehicles, which was such a success, the horse drawn variants were quickly phased out. In civilian emergency care, dedicated ambulance services were frequently managed or dispatched by individual hospitals, though in some areas, telegraph and telephone services enabled police departments to handle dispatch duties.^[22]

The equipment carried by the ambulance was changing fast at this time. Traction splints were introduced during World War I, and were found to have a positive effect on the morbidity and mortality of patients with leg fractures. Two-way radios became available shortly after World War I, enabling for more efficient radio dispatch of ambulances. Shortly before World War II, then, a modern ambulance carried advanced medical equipment, was staffed by a physician, and was dispatched by radio. It was frequently found that ambulances were hearses - the only available vehicle that could carry a recumbent patient - and were thus frequently run by funeral homes, these vehicles which could serve for either purpose were known as combination cars.^[22][29]

Air ambulances

Australian Flying Doctor Service vehicles in 1954

During World War One, aviation moved from experimentation to a powerful military force, and following the war, with a surplus of aircraft in circulation, new uses were found for the aircraft. This included the conversion of planes throughout the world in to ambulance planes. Although in 1917 , Lieutenant Clifford Peel, a medical student, outlined a system of fixed-wing aircraft and ground facilities designed to provide medical services to the Australian Outback, the first custom built air ambulances did not come in to existence until the late 1920s. These ideas became reality under the guidance of the Very Reverend John Flynn in 1928 when the Australian Inland Mission service established the Aerial Medical Service, a one year experimental program. Physicians in this program had several responsibilities, one of which was to fly out to a patient, treat the patient, and fly the patient to a hospital if the physician could not deliver adequate care on scene. Eventually, this experiment became the Royal Flying Doctor Service of Australia.^[15]

World War Two

In much of the world, ambulance quality fell sharply during the second world war, as physicians, needed by the armed services, were pulled off of ambulances. In England, during the Battle of Britain, the need for ambulances was so great that vans were commandeered and pressed into service, often carrying several victims at once. Following the war, physicians would continue to ride ambulances in some countries, but not in others. Other vehicles, including civilian and police cars were pressed in to service to transport patients due to a lack of a dedicated resource.^[22][30] Military ambulances such as the Austin K2 were used both in the combat areas and on the Home Front

Move to life saving, not just transporting

A 1964 police cruiser, which is also fitted to transport patients. This was used before the advent of EMS services.

This situation persisted into the 1960s, when a chain events occurred that led to a redesign of the services provided by ambulance crews, and thus of the ambulance itself: CPR was developed and accepted as the standard of care for out-of-hospital cardiac arrest; defibrillation, based in part on an increased understanding of heart arrhythmias, was introduced, as were new pharmaceuticals to be used in cardiac arrest situations; in Ireland, a mobile coronary care ambulance successfully resuscitated patients using these technologies;^[31] and well-developed studies demonstrated the need for overhauling ambulance services. These studies placed pressure on governments to improve emergency care in general, including the care provided by ambulance services. Part of the result was the creation of standards in ambulance construction concerning the internal height of the patient care area (to allow for an attendant to continue to care for the patient during transport), in the equipment (and thus weight) that an ambulance had to carry. Few, or perhaps none of the then-available ambulances could meet these standards.^[22][32]

A 1973 Cadillac Miller-Meteor ambulance. Note the higher roof, with more room for the attendants and patient

Most ambulances at the time, were built on a car chassis (often based on hearses), which could not accept the weight and other demands of the new standards; van (and later, light truck) chassis would have to be used instead.^[22][32]

Ambulance design therefore underwent major changes in the 1970s. The early van-based ambulances looked very similar to their civilian counterparts, having been given a limited amount of emergency vehicle equipment such as audible and visual warnings, and the internal fittings for carrying medical equipment, most notably a stretcher.

As time went on, ambulances matured in parallel to the newly developed EMS, gaining the capacity to carry additional equipment (both portable and permanently installed) as EMTs and paramedics added this equipment to their arsenal. .

Modern vehicles

Israeli EMS's contemporary civilian armored Mobile Intensive Care Unit. Used for response to ongoing terrorist incidents, it is based off a super-duty Ford E-450 chassis.

Modern ambulances are now often custom built (see Design and construction below), and as well as the specialist medical equipment now built in to the ambulances, industry wide improvements in vehicle design have had an impact, including improvements in audible and visual warning equipment to help protect crews in vulnerable situations (such as at a Road Traffic Collision), and general improvements such as ABS, which are particularly valuable for ambulances, due to the speeds reached and the weight carried. There have also been improvements to help safeguard the health and welfare of ambulance crews, such as the addition of patient tail lifts, ramps and winches,^[33] to cut down on the amount of manual handling a crew must perform.

Ambulance design is still evolving, largely due to the growing skills and role of Paramedics and other ambulance crew, which require specialist equipment. Other factors driving improvement include the need to help protect ambulance crews from common accidents, such as traffic collisions and rarer, but potentially catastrophic incidents such as terrorist activities.

Design and construction

Ambulance interiors are often cramped, as seen in this Brazilian ambulance

Successful ambulance design must take in to account the local conditions and available infrastructure. Maintained roads are necessary for the familiar 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 make up for a paucity of good roads. Appropriate fuel must be readily available and service facilities are necessary to maintain the vehicle.

Methods of summoning (e.g. telephone) and dispatching ambulances usually rely on electronic equipment, which itself often relies on an intact power grid. Similarly, modern ambulances are equipped with two-way radios^[34] or cellular telephones to enable them to contact hospitals, either to notify the appropriate hospital of the ambulance's pending arrival, or, in cases where physicians do not form part of the ambulance's crew, to confer with a physician for medical oversight.^[35]

Ambulances often have two manufacturers. The first is frequently a manufacturer of light trucks (or previously, cars) such as Mercedes-Benz or Ford. The second manufacturer purchases the vehicle (which is sometimes purchased incomplete, having no body or interior behind the driver's seat) and turns it into an ambulance by adding bodywork, emergency vehicle equipment, and interior fittings. This is done by one of two methods - either coachbuilding, where the modifications are started from scratch and built on to the vehicle, or using a modular system, where a pre-built 'box' is put on to the empty chassis of the ambulance, and then finished off.

Modern ambulances are typically powered by internal combustion engines, which can be powered by any conventional fuel, including diesel, gasoline or liquefied petroleum gas,^[36][37] depending on the preference of the operator and the availability of different options. Colder regions often use gasoline powered engines, as diesels can be difficult to start when they are cold. Warmer regions may favor diesel engines, as they are thought to be more efficient and more durable. Diesel power is sometimes chosen due to safety concerns, after a series of fires involving gasoline powered ambulances during the 1980s. These fires were ultimately attributed in part to gasoline's higher volatility in comparison to diesel fuel.^[38] The type of engine may be determined by the manufacturer: Ford^[39][40][41] will only sell vehicles for ambulance conversion if they are diesel powered.

Safety

Like all vehicles, ambulances may be involved in collisions. Ambulances, like other emergency vehicles, are required to operate in all weather conditions, including those during which civilian drivers often elect to stay off of the road. Also, the ambulance crew's responsibilities to their patient often preclude their use of safety devices such as seat belts. Research has shown that ambulances are more likely to be involved in motor vehicle collisions resulting in injury or death than either fire trucks or police cars. Unrestrained occupants, particularly those riding in the patient-care compartment, are particularly vulnerable.^[42] When compared to civilian vehicles of similar size, one study found that on a per-accident basis, ambulance collisions tend to involve more people, and result in more injuries.^[43] An eleven-year retrospective study concluded in 2001 found that although most fatal ambulance crashes occurred during emergency runs, they typically occurred on improved, straight, dry roads, during clear weather.^[44] Safety is thus of special concern in ambulance design.

Equipment

In addition to the equipment directly used for the treatment of patients, ambulances may be fitted with a range of additional equipment which is used in order to facilitate patient care. This could include:

• Two Way Radio - One of the most important pieces of equipment in modern emergency medical services as it allows for the issuing of jobs to the ambulance, and can allow the crew to pass information back to control or to the hospital (for example a priority ASHICE message to alert the hospital of the impending arrival of a critical patient.)^[34][35] More recently many services world wide have moved from traditional UHF/VHF sets, which can be monitored externally, to more secure systems, such as those working on a GSM system, such as TETRA
• Mobile Data Terminal - Some ambulances are fitted with Mobile Data Terminals (or MDTs), which are connected wirelessly to a central computer, usually at the control center. These terminals can function instead of or alongside the two way radio and can be used to pass details of jobs to the crew, and can log the time the crew was mobile to a patient, arrived, and left scene, or fulfill any other computer based function.^[45]
• Evidence gathering CCTV - Some ambulances are now being fitted with video cameras used to record activity either inside or outside the vehicle. They may also be fitted with sound recording facilities. This can be used as a form of protection from violence against ambulance crews,^[46] or in some cases (dependent on local laws) to prove or disprove cases where a member of crew stands accused of malpractice.
• Tail lift or ramp - Ambulances can be fitted with a tail lift or ramp in order to facilitate loading a patient without having to undertake any lifting. This is especially important where the patient might be obese. There may also be equipment linked to this such as winches which are designed to pull heavy patients in to the vehicle.^[33]
• Trauma lighting - In addition to normal working lighting, ambulances can be fitted with special lighting (often blue or red) which is used when the patient becomes photosensitive.
• Air conditioning - Ambulances are often fitted with a separate air conditioning system to serve the working area from that which serves the cab. This helps to maintain an appropriate temperature for any patients being treated, but may also feature additional features such as filtering against airborne pathogens.

Intermediate technology

In parts of the world which lack a high level of infrastructure, ambulances are designed to meet local conditions, being built using intermediate technology. Ambulances can also be trailers, which are pulled by bicycles, motorcycles, tractors, or animals. Animal-powered ambulances can particularly useful in regions that are subject to flooding. Three-wheeled motorcycles are also used, though they are subject to some of the same limitations as more traditional over-the-road ambulances. The level of care provided by these ambulances varies between merely providing transport to a medical clinic to providing on-scene and continuing care during transport.^[7]

The design of intermediate technology ambulances must take into account not only the operation and maintenance of the ambulance, but its construction as well. The robustness of the design becomes more important, as does the nature of the skills required to properly operate the vehicle. Cost-effectiveness can be a high priority.^[8]

Appearance and markings

Emergency ambulances are highly likely to be involved in hazardous situations, including incidents such as a road traffic collision, as these emergencies create people who are likely to be in need of treatment. They are required to gain access to patients as quickly as possible, and in many countries, are given dispensation from obeying certain traffic laws (for instance, they may be able to treat a red traffic light or stop sign as a yield ('give way') sign, or be permitted to break the speed limit.

For these reasons, emergency ambulances are often fitted with visual and/or audible warnings to alert road users.

Visual warnings on an ambulance can be of two types - either passive or active.

Passive visual warnings

An ambulance in the UK fully marked with passive visual warnings (retro-reflective battenburg pattern)

The passive visual warnings are usually part of the design of the vehicle, and involve the use of high contrast patterns. Older ambulances (and those in developing countries) are more likely to have their pattern painted on, whereas modern ambulances generally carry retro-reflective designs which reflect light from car headlights or torches. Popular patterns include 'checker board' (alternate coloured squares, sometimes called 'Battenburg', named after a type of cake), chevrons (arrowheads - often pointed towards the front of the vehicle if on the side, or pointing vertically upwards on the rear) or stripes along the side (these were the first type or retro-reflective device introduced, as the original reflective material, invented by 3M, only came in tape form). In addition to retro-reflective markings, some services now have the vehicles painted in a bright (sometimes fluorescent) yellow or orange for maximum visual impact. In Europe this colour is defined as Euro Yellow RAL 1016 for emergency service vehicles.

London Ambulance displays reversed wording and 'Star of Life'

Red Cross and Red Crescent Symbols

Maltese cross

Typical St. Florian's cross

Another passive marking form is the word ambulance spelled out in reverse on the front of the vehicle. This enables drivers of other vehicles to more easily identify an approaching ambulance in their rear view mirrors. Ambulances may display the name of their owner or operator, and a telephone number which may be used to summon the ambulance.

Ambulances may also carry an emblem (either as part of the passive warning markings or not), such as a Red Cross, Red Crescent or Red Diamond (collective known as the Protective Symbols). These are symbols laid down by the Geneva Convention, and all countries signatory to it agree to restrict their use to either (1) Military Ambulances or (2) the national Red Cross or Red Crescent society. Use by any other person, organization or agency is in breach of international law. The protective symbols are designed to indicate to all people (especially combatants in the case of war) that the vehicle is neutral and is not to be fired upon (more detail below in “military ambulances”), hence giving protection to the medics and their casualties, although this has not always been adhered to. In Israel, Magen David Adom, the Red Cross member organization use a Red Star of David, but this does not have recognition beyond Israeli borders.

The Star of Life is widely used, and was originally designed and governed by the U.S. National Highway Traffic Safety Administration, after legal action by the Red Cross over alleged misuse of their symbol (by using a bright orange cross, felt to be too similar to the Red Cross device). It indicates that the vehicle's operators can render their given level of care represented on the six pointed star.

Ambulance services that have historical origins in the Order of St John often use the Maltese cross to identify their ambulances. This is especially important in countries such as Australia, where St John Ambulance operate one state and one territory ambulance service, and all of Australia's other ambulance services use variations on a red Maltese cross.^{[47][48][49][50]}

Fire service operated ambulances may display the Cross of St. Florian (often, incorrectly, called a Maltese cross) as this cross is frequently used as a fire department logo (St Florian being the patron saint of firefighters).^[51]

Active visual warnings

German Ambulance and Response car displaying active visual warning beacons