Emergency medical services (EMS) vehicles have evolved as EMS providers` needs and capabilities have changed. Before the 1960s, the victim in a medical emergency did not receive much more medical assistance besides being transported to the hospital. Since ambulances often were staffed only by a driver, ambulance services until that time offered little in the way of lifesaving care. As EMS in the fire service has grown, EMS vehicles have become dual-role, much like the emergency personnel who staff them. Today, ambulances are typically staffed with two to four trained medical providers and are designed and equipped to deal with a myriad of medical, fire, and rescue emergencies.


The first recorded ambulances date back to the Crusades, and the first prehospital care was provided during the Napoleonic Wars in the late 18th and early 19th centuries. America`s first ambulance service was reportedly started by the Union Army in 1862 and transported wounded soldiers from a medical aid station near the battle lines to a field hospital outside the range of artillery fire. City ambulance services followed soon after in many parts of the country, typically established by hospitals using horse-drawn wagons with an enclosed patient compartment. This system–hospitals providing a vehicle to transport patients when necessary–continued in urban areas of the country through the 1930s, while rural areas had no prehospital system other than local doctors making house calls.

During World War II, the loss of personnel to the war effort resulted in many hospitals` turning their ambulance services over to volunteer groups and agencies capable of operating motor vehicles for this type of service. Typically, this was either a fire department, a police department, or a funeral home. In some places, local citizens joined together to provide the service, forming independent ambulance corps or rescue squads. At this time, ambulance services were still little more than “horizontal taxi” operations, as medical training, if any, was rudimentary.

In the 1970s, Cadillac- and International Carryall-type ambulances gave way to high-rise vans and modular units on pickup truck chassis. In the 1980s, the popularity of modular units on van chassis grew, and most ambulances were on Ford chassis. Both types of modular units (on pickup and van chassis) as well as high-rise vans are still the primary ambulance designs used today.

In the 1970s and 1980s, many fire departments began providing EMS first-response services. A first-response system is a prehospital EMS system where the closest emergency response unit with EMS-trained personnel is dispatched along with a transporting EMS unit. The first-response personnel may be trained at the first- responder level; however; more often they are trained at the EMT, EMT-I, or paramedic level. The first-response unit is usually a nontransporting unit–typically an engine company, but often a rescue or squad company or even a ladder company. Some fire departments use ambulances as first-response units but have arrangements for the transport of noncritical patients with a private or separate-service ambulance company. Others operate under an agreement in which an ALS firefighter accompanies the patient to the hospital in the ambulance.


One option for delivering ALS first response is to place paramedics aboard engine companies, increasingly referred to as “front-loaded ALS,” and requires cross-trained personnel. This delivery mechanism allows ALS initiation prior to the ambulance`s arrival and increases efficiency because personnel fill multiple roles.

One disadvantage of paramedic engine companies is that sometimes an engine company is put out of service when a paramedic company must accompany a patient to the hospital. In services in which this happens regularly, as in those using BLS ambulances to respond with paramedic engine companies, fire departments often assign two paramedics to an engine so that the company does not need to go out of service.


Many departments respond to EMS calls in rescue trucks, which are similar to plumbers` trucks. Others are huge, ladder truck-sized vehicles equipped for any types of rescue imaginable. From the EMS aspect, these are simply first-response nontransport vehicles, equipped with the appropriate level of equipment and staffed with appropriately trained personnel.


Some fire departments serving rural areas or that respond mostly to BLS calls place their paramedics in chase cars: smaller, nontransport-capable vehicles that carry one or two paramedics and the requisite emergency medical equipment. Chase cars are generally centrally located in a given geographic response area. They are dispatched to medical emergencies along with an ambulance (either ALS or BLS) and sometimes with a first-response engine company (usually at the BLS level). This allows communities desiring ALS care to implement it without having to put paramedics in every station or on each piece of apparatus.

In some outlying areas, chase cars routinely perform so-called intercepts. Under this concept, distant BLS ambulances with critical patients start transporting the patient to the hospital and arrange a rendezvous with a chase car somewhere along the route. ALS care can start as soon as possible without having ALS capabilities permanently assigned to remote or rural areas or having to wait on the scene for the ALS unit to arrive.

Chase cars are slightly more flexible than placing paramedics in ambulances because they can respond more easily in city traffic and in a wider variety of terrain/road conditions in rural areas. Chase cars allow a paramedic team to assess the patient and determine whether ALS transport is warranted. If the patient assessment does not indicate a need for ALS care, the ambulance crew can transport the patient and the chase car can stay in service in its response area. Should ALS care en route to the hospital be necessary, a paramedic from the chase car can ride with the patient in the ambulance, and the second chase car crew member or a firefighter can follow with the chase car. If the second chase car`s crew member is a paramedic, the unit can often stay in service for another call.

There is no classification system or set of federal specifications for chase cars. In general, whatever a fire department is using as its staff or command vehicles should suffice for EMS duty. In some systems, the chase cars carry extra supplies (backboards, oxygen, disaster equipment, and so on), specialized medications (such as haz-mat antidote kits), or other equipment such as turnout gear or water rescue equipment. The key is to match the vehicle to the job it is used to perform.


There are three general styles of ambulance construction. Type I ambulances have a modular patient compartment built on a truck chassis. A modular patient compartment can be dismounted from one chassis and placed on another. This allows patient compartments to remain in service after a chassis is replaced. Other than a small window, there is generally no connection between the driver`s cab and the patient compartment on a Type I ambulance. To get from the front cab to the patient compartment, you must exit the cab and enter the patient compartment from the side or rear doors.

A Type II ambulance is a van with a raised roof. Since the driver`s cab and the patient compartment are integrated, Type II ambulances allow a person to walk between the driver and passenger compartments. This not only facilitates communication between the front and the back of the vehicle but also allows the driver to get to the patient compartment quickly should the need arise.

Types I and III ambulances are similar in size and design; however, Type III ambulances are built on a van chassis. This allows the walk-through feature of a Type II ambulance to be combined with the modular feature of a Type I.

Some areas have rugged or unusual geographic and weather conditions (e.g., mountains, desert, water, heavy snowfall, and ice) that demand ambulances with special capabilities. EMS vehicles in such areas should be especially designed for their specific missions. In the U.S. Virgin Islands, for example, the EMS system transports patients from the island of St. John to a hospital on the island of St. Thomas by a marine ambulance–a boat specifically fitted for ambulance duty. Other specialized ambulances include four-wheel-drive vehicles and snowmobiles.

In the 1990s, larger truck chassis were used for Types I and III ambulances. These larger chassis had heavier and larger payloads, more power and room, and a longer lifespan in time and mileage. Also, they could be two- or four-door models. The larger chassis allowed departments to add more “stuff,” and some combined the attributes of a minipumper with that of the ambulance.


Today, it is not uncommon for a fire department to have an ambulance with a PTO pump and water tank large enough to supply a 134-inch attack line or two. This type of unit may be called a transport-capable fire/rescue unit or a suppression ambulance. Some have a Class A or compressed-air foam system that allows smaller water tanks without diminishing the suppression capability. One manufacturer has adapted this concept by installing an electric water pump and compressed air from SCUBA tanks to create a compact, self-contained compressed-air foam firefighting system.

A first-response vehicle currently in the works will combine fire suppression, ALS response, and patient transport in one multipurpose apparatus. These units will ride on a custom four-door chassis designed for maneuverability through crowded streets and around tight corners. Several configurations are designed especially for the fire service, not just adapted for it, enabling departments to determine how best to use them. The idea is to provide fire departments with a vehicle that can respond quickly to most common calls while saving wear and tear on larger, more expensive apparatus. This unit will be useful for the fire service “community-based healthcare teams” of the future.

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All fire departments should have a very good understanding of their EMS demands, including the unique challenges of their terrain and levels/types of services that will be provided. This information will need to be carried over into the vehicle design process. (It is important to note that ambulances purchased using federal money or for use on a federal installation must adhere to the current edition General Services Administration specification KKK-A-1822.) Regardless of the funding mechanism, the type and design of EMS vehicles must be based on the needs of the community and how EMS and other services should be provided by the fire department. EMS is changing, and the way a fire department responds to these emergencies continues to evolve as well. n

GORDON M. SACHS is a frequent contributor to Fire Engineering. He wrote the chapter on EMS in The Fire Chief`s Handbook, Fifth Edition (Fire Engineering Books, 1995) and is author of the forthcoming A Chief Officer`s Guide to Fire Service EMS (Fire Engineering). He has more than 20 years of fire service and EMS experience in both career and volunteer areas, is a graduate of the National Fire Academy`s Executive Officer Training Program, and is an adjunct faculty member of the Academy. He directs the IOCAD Emergency Services Group, a consulting firm in Emmitsburg, Maryland.

(Top left) Larger chassis are becoming more common on ambulances due to the increased payload and durability. (Photo by author.) (Top right) Some fire departments still use a plumbers` truck style for a first-response EMS vehicle. (Photo by author.) (Middle) Many departments are now purchasing ambulances with first-response firefighting capabilities. (Photo courtesy of Emergency One.) (Bottom left) Type I ambulance. (Photo courtesy of Emergency One.) (Bottom right) Type III ambulance. (Photo courtesy of Emergency One.)

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