School bus

19th century: Kid hacks

A 1912 Studebaker truck with a school bus body.

In the second half of the 19th century, many rural areas of the United States and Canada were served by one-room schools. For those students who lived beyond practical walking distance from school, transportation was facilitated in the form of the kid hack; at the time, "hack" was a term referring to certain types of horse-drawn carriages.^[6]

One of the longest-running school bus manufacturers, Wayne Works (later Wayne Corporation), started producing its first school wagons in Indiana in the late 1880s.^[6][7] Essentially a re-purposed farm wagon with the addition of interior bench seats, the design featured a rear entrance door. As kid hacks were horse-drawn vehicles, the feature was intended in order to avoid startling the horses while loading or unloading passengers.

1900–1930: Motorized school vehicles

"Blue Bird No. 1", the first bus constructed by A.L. Luce, founder of Blue Bird Body Company. The oldest known surviving school bus in the United States, it is based on a 1927 Ford Model T chassis.

After the first decade of the 20th century, student transport underwent a major transition, as vehicles transitioned from horse-drawn wagons towards "horseless" automotive chassis. In terms of overall configuration, few initial changes were made, as wagon bodies were adapted to truck frames. For the passenger compartment, the rear entry door and perimeter bench seating remained. For most of the first three decades, school bus bodies were given little, if any, weather protection, sometimes consisting of a tarpaulin stretched above the passenger seating.

In 1927, Ford dealership owner A.L. Luce produced a bus body for a 1927 Ford Model T. Unlike previous wood-bodied buses, Luce used wood only to frame the body of the bus, paneling the body in steel; this would become the first bus produced by what would later become bus manufacturer Blue Bird. While the bus was constructed with a roof, its only weather protection was afforded by roll-up canvas side curtains.

1930s: All-metal school buses

Late 1930s school bus

During the 1930s, several advances in school buses were seen that would change its design and production forever. To better adapt automotive chassis design, school bus entry doors were moved from the rear to the front curbside, becoming a door operated by the driver (to ease loading passengers and improve forward visibility). However, school buses retained the rear door, re-purposed as an emergency exit. Following the introduction of the steel-paneled 1927 Luce bus, school bus manufacturing began to transition towards all-steel bus bodies. In 1930,^[6] both Wayne and Superior introduced all-steel school buses, with the latter introducing a body with safety glass windows.

As school bus design paralleled design of light to medium-duty commercial trucks of the time, the advent of forward-control trucks would have their own influence on school bus design. In an effort to gain extra seating capacity and visibility, Crown Coach built its own cabover school bus design from the ground up.^[8][9][10] The highest-capacity school bus of the time,^[9] the 76-passenger Crown Supercoach was aptly named, as many California school districts operated in terrain requiring heavy-duty vehicles.^[10] As the 1930s progressed, flat-front school buses began to follow motorcoach design in styling as well as engineering, partially the reason the industry adopted "transit-style" in naming them. In 1940, the first mid-engined transit school bus was produced by Gillig in California.^[11]

1940s: Transition in role

In the years leading up to World War II, school buses would begin to take on a new role in the education system. This would lead to school districts purchasing and operating their own fleets of school buses, taking over from buses owner-operated by local individuals.

In all but the most isolated areas, the one-room schools from the turn of the century were being phased out and consolidated in favor of the multi-grade schools seen in urban areas. Following the war and the rise of suburban growth in North America, the need for school busing came into use for more than just rural areas; beyond a certain distance from home, community design often made walking to school impractical, particularly as students progressed into high school.

1950s–1960s: Adapting to demand

Restored 1950s Reo school bus with an Oneida body

1961 International Harvester B-163 with a Thomas Car Works body

At the beginning of the 1950s, the baby boom generation began their education, leading to a significant increase in student populations across North America; this would be a factor that would directly influence school bus production into the early 1980s. To accommodate the larger student populations, school buses began to grow in size, adding extra rows of seats for the bus body. Coinciding with the larger bodies, truck manufacturers began to offer heavier-duty bus chassis. The same applied to transit-style school buses, as the first diesel-powered school bus was introduced in 1954 and the first tandem axle school bus in 1955 (a Crown Supercoach, with a 91-passenger seating capacity). At the end of the 1950s, a new option was developed, which is specified in many school buses today: a curbside wheelchair lift to transport wheelchair-bound passengers.

As full-size school buses grew larger during the 1950s and early 1960s, they became difficult to navigate the crowded, narrow streets of urban neighborhoods; other rural routes were extremely isolated, with roads that could not accommodate full-size buses. To fill this role, yellow-painted vehicles such as the International Travelall and Chevrolet Suburban came into use. As they entered production in the 1960s, passenger vans such as the Chevrolet Van/GMC Handi-Van, Dodge A100, and Ford Econoline were converted to school bus use, largely by the addition of red warning lights and yellow paint. A drawback to using passenger vans and utility vehicles is that, along with their lower seating capacity, they could not offer the same level of safety as a full-size school bus.

1970s: Focus on safety of kids

1970s Wayne Lifeguard

During the 1970s, school buses would undergo a number of design upgrades related to safety. While many changes were related to protecting passengers, others were intended to minimizing the chances of traffic collisions. To decrease confusion over traffic priority (increasing safety around school bus stops), federal and state regulations were amended, requiring for many states/provinces to add amber warning lamps inboard of the red warning lamps. Similar to a yellow traffic light, the amber lights are activated before stopping (at 100–300 feet (30.5–91.4 m) distance), indicating to drivers that a school bus is about to stop and unload/load students. Adopted by a number of states during the mid-1970s, amber warning lights became nearly universal equipment on new school buses by the end of the 1980s. To supplement the additional warning lights, to help prevent drivers from passing a stopped school bus, a stop arm was added to nearly all school buses; connected to the wiring of the warning lights, the deployable stop arm extended during a bus stop with its own set of red flashing lights.

During the 1960s, as with standard passenger cars, concerns began to arise for passenger protection in catastrophic traffic collisions. At the time, the weak point of the body structure was the body joints; where panels and pieces were riveted together, joints could break apart in major accidents, with the bus body causing harm to passengers.^[15] After subjecting a bus to a rollover test in 1964, in 1969, Ward Body Works pointing that fasteners had a direct effect on joint quality (and that body manufacturers were using relatively few rivets and fasteners).^[16] In its own research, Wayne Corporation discovered that the body joints were the weak points themselves. In 1973, to reduce the risk of body panel separation, Wayne introduced the Wayne Lifeguard, a school bus body with single-piece body side and roof stampings. While single-piece stampings seen in the Lifeguard had their own manufacturing challenges, school buses of today use relatively few side panels to minimize body joints.

From 1939 to 1973, school bus production was largely self-regulated. In 1973, the first federal regulations governing school buses went into effect, as FMVSS 217 was required for school buses; the regulation governed specifications of rear emergency exit doors/windows.^[15][16] Following the focus on school bus structural integrity, NHTSA introduced the four Federal Motor Vehicle Safety Standards for School Buses, applied on April 1, 1977, bringing significant change to the design, engineering, and construction of school buses and a substantial improvement in safety performance.

While many changes related to the 1977 safety standards were made under the body structure (to improve crashworthiness), the most visible change was to passenger seating. In place of the metal-back passenger seats seen since the 1930s, the regulations introduced taller seats with thick padding on both the front and back, acting as a protective barrier. Further improvement has resulted from continuing efforts by the U.S. National Highway Traffic Safety Administration (NHTSA) and Transport Canada, as well as by the bus industry and various safety advocates. As of 2018 production, all of these standards remain in effect.^[17]

In the 1970s, school busing expanded further, under controversial reasons; a number of larger cities began to bus students in an effort to racially integrate schools. Out of necessity, the additional usage created further demand for bus production.

As manufacturers sought to develop safer school buses, a new generation of small school buses was developed. In the mid-1970s, the Wayne Busette and Blue Bird Micro Bird were introduced. To replace conversions of passenger vans, manufacturers began production of bus bodies using cutaway van chassis; the combination offered additional seating capacity alongside safer body construction.

1980s–1990s: Transition in production

1980s Ford B700 with a Thomas body

1990s Blue Bird TC/2000 RE

By the beginning of the 1980s, nearly the entire baby-boom generation had completed its high-school education, which led to a decrease in student populations in North America. Coupled with the recession economy of the early 1980s, the school bus production industry was left with a large degree of overcapacity; several manufacturers were in financial ruin.

During the 1980s and 1990s, safety would remain a highlight of many school bus redesigns and model introductions. To increase loading-zone visibility, the design of bus bodies began to move the driver upward, outboard, and forward; windshields grew larger in size. Improving the ergonomics of the drivers' compartment was intended to decrease driver distraction, which led to improved layouts of controls and switches. To avoid stalling in stop-and-go driving (and in potentially dangerous places, such as intersections or railroad crossings), automatic transmissions had begun to replace manual transmissions during the 1980s. As a result of the 1970s fuel shortages, steps were also taken to improve the fuel economy of school buses. In the 1980s, manufacturers began to include diesel engines as options in conventional and small school buses; previously, diesel engines were considered a premium option only used on transit-style school buses. In 1986, Navistar International became the first chassis manufacturer to phase out gasoline engines entirely. Other manufacturers followed suit, and diesel engines replaced gasoline engines in virtually all full-size school buses by the mid-1990s.

In 1986, with the signing of the Commercial Motor Vehicle Safety Act, school bus drivers across the United States became required to acquire a commercial driver's license (CDL); while still issued by individual states, the federal CDL requirement ensured that drivers of large vehicles such as school buses have a consistent training level.^[7] School buses are generally considered Class C vehicles with passenger and namesake endorsements, but the highest-capacity versions require a Class B license (based on their higher GVWR).

The demand for better forward visibility and better turning radius led to a major expansion of market share for transit-style school buses in the late 1980s and early 1990s. Initially, this was led by the 1986 Wayne Lifestar; however, the AmTran Genesis, Blue Bird TC/2000, and Thomas Saf-T-Liner MVP would prove far more successful. In 1996, AmTran introduced the AmTran RE, the first low-cost rear-engine school bus.

During the 1990s, an emerging trend among body manufacturers was mergers, joint ventures, and acquisitions among major chassis suppliers. Navistar International became the owner of AmTran (formerly Ward), Spartan Motors purchased Carpenter, and Thomas Built Buses was acquired by Freightliner.

2000s: 21st-century school bus

Blue Bird Vision

By the beginning of the 21st century, manufacturer consolidation and industry contraction would necessitate production changes among remaining school bus manufacturers. Gone were the days of customers picking and choosing school bus body and chassis separately; the acquisition of AmTran and Thomas along with the General Motors supply arrangement with Blue Bird had reduced the separate combinations available to build. Although the aspect of choice was disappearing, the decreased complexity paved the way for new product innovations previously thought impossible.

In the past, conventional-style buses were bodied on a chassis supplied by a separate manufacturer. For 2004, two manufacturers introduced conventional-body school buses that integrated both body and chassis within a single manufacturer. Blue Bird introduced the Vision; in the fashion of the All American, the chassis was designed by the company specifically for bus use and built in its own factory. Thomas Built Buses introduced the Thomas Saf-T-Liner C2; although the chassis was derived from the Freightliner Business Class M2, the chassis and the body of the C2 were designed together as a unique vehicle. A key trait of both the Vision and the C2 was improved visibility around the loading zone; both vehicles feature highly sloped hoods and extra glass around the entry door of the bus. In a major change from manufacturing precedent, the C2 was the first use of adhesive bonding to join body panels and minimizing the need for rivets in a school bus.

After the sale of the General Motors P-chassis to Navistar subsidiary Workhorse in 1998, the Type B bus configuration largely began to disappear. In their place, cutaway versions of Class 4–5 trucks began to appear; various school buses utilized Chevrolet/GMC C4500 and International 3200 cutaway cabs. In 2006, IC Bus introduced the BE200, the first Type B bus with a fully cowled chassis (a scaled-down Type C body).

During the 1990s, mergers and acquisitions would continue to influence school bus production; however, aside from the failure of startup manufacturer Liberty Bus, contraction was largely absent. In 2007, Collins Bus Corporation, the largest independent manufacturer of Type A buses, acquired Canadian manufacturer Corbeil out of bankruptcy. Corbeil joined Ohio-based manufacturer Mid Bus as a Collins subsidiary; manufacturing of all three product lines was consolidated at the Kansas factory owned by Collins. In 2009, Blue Bird and Girardin entered into a joint venture; Girardin now produces the entire small-bus product line for Blue Bird.^[18]

During the 2000s, safety devices were updated, as lap-type seatbelts were largely replaced by 3-point seatbelts. School bus crossing arms, first introduced in the late 1990s, were adopted by a number of jurisdictions. Electronics took on a new role in school bus operation. To increase child safety and security, alarm systems have been developed to prevent children from being left on unattended school buses overnight.^[19]

2010s: "Green" school buses

During the past decade, a number of changes have been made to develop a new generation of school buses; many of the changes are focused on producing environmentally friendly vehicles. In 2009, Blue Bird introduced a propane-fueled version of its Vision conventional, becoming the first manufacturer to sell a propane-fuel school bus from the factory. In 2011, Lion Bus (Autobus Lion) of Saint-Jérôme, Quebec marked the return of full-size bus production to Canada. In partnership with Spartan Motors,^[20] the company marked the first all-new manufacturer of full-size school buses since 1992. Producing a single conventional-style bus body, Lion became the first manufacturer to adopt design primarily with composite panels in place of the traditionally used steel.

During the mid-2010s, although diesel-fuel engines have remained the primary source of school bus power, school bus manufacturers have expanded offerings of alternative-fuel vehicles, with propane and CNG becoming offered through several manufacturers by 2015. In a reversal from the 1990s, gasoline engines became available in conventional-style school buses in 2016, offering quieter interiors along with simpler emissions equipment.^[21]

While hybrid diesel-electric school buses saw little interest among operators, several school buses have been produced with fully electric powertrains. In 2012, Trans Tech produced a limited series of the eTrans, a cutaway-body bus based upon the Smith Electric Newton electric truck; the eTrans was replaced in 2014 by the SSTe, a Trans Tech/Ford E450 school bus converted to electric power. In 2015, Autobus Lion introduced the eLion, the first full-sized fully electric school bus. In 2017, Blue Bird announced intentions to produce electric-power versions of Type A, Type C, and Type D buses.^[22]

In the past decade, onboard GPS tracking devices have taken on a dual role of fleet management and location tracking. Not only does GPS tracking allow for internal management of costs, but it can be used to alert waiting parents and students of the real-time location of their bus.^[23] This is in use in the United States as well as worldwide markets, such as India.^[24]

Configuration

Outside of North America, buses utilized for student transport are derived from existing vehicles: transit buses, coaches, and minibuses. In the United States and Canada, numerous regulations at the state and federal require school buses to be manufactured as a purpose-built vehicle separate from other buses.

Of the purpose-built school buses produced in North America, there are four configurations of school buses.^[1] All school buses are of single deck design, with step entry. In the United States, school buses are restricted to a maximum width of 102 in (2.59 m) and a maximum length of 45 ft (13.7 m).^[27][28] Depending on specifications, school buses are currently designed with a seating capacity with up to 90 passengers.

School bus configurations^[1][29][30]

	Type A		Type B	Type C	Type D
Style	(cutaway van)		(integrated/conventional)	(conventional)	(transit style)
GVWR	Type A-I	≤ 10,000 lb (4,500 kg)	≥ 10,000 lb (4,500 kg)
	Type A-II	≥ 10,000 lb (4,500 kg)
Driver's door	Yes		No	No	No
Entrance door	Behind front wheels				Ahead of front wheels
Passenger capacity (minimum)	>10		> 10	>10	> 10
Engine location	Front		Front (beneath windshield and beside driver)	Front	Front, midship, or rear
Example	Trans Tech/Ford E-450		IC BE-Series	Thomas Saf-T-Liner C2	IC Bus RE-Series

Production (North America)

In the United States and Canada, school buses are currently produced by nine different manufacturers. Four of them—Collins Industries, Starcraft Bus, Trans Tech, and Van Con — specialize exclusively in small buses. Thomas Built Buses and Blue Bird Corporation (the latter, through its Micro Bird joint venture with Girardin)—produce both small and large buses. IC Bus and Lion Bus produce full-size buses exclusively.

In business since 2011, Quebec-based Lion Bus is currently in the process of becoming an electric vehicle manufacturer; in 2017, the company renamed itself the Lion Electric Company (in French, La Compagnie Électrique Lion); the company produces bodies on conventional-style chassis produced by Spartan Motors. In the past, Canada was also home to facilities of several U.S. firms (Blue Bird, Thomas, Wayne); Canadian-produced school buses were exported to the United States, and Canada imported many U.S.-produced buses. Domestically, the Quebec-based firm Corbeil manufactured full-size and small school buses from 1985 to 2007. In 2008, it was purchased by Collins Industries, largely to serve as the Canadian brand of Collins.

Other school buses

Multi-Function School Activity Bus (MFSAB) in Houston, Texas.

In both public and private education systems, outside of school buses in regular route service, there are two other uses that involve school buses. An "activity bus" is a school bus used for providing transportation for students. Instead of being used in route service (home to school), the intended use of an activity bus is for transporting students solely for extracurricular activities. Depending on individual state and provincial regulations, the bus used for this purpose can either be a regular yellow school bus or a dedicated unit for this purpose. Dedicated activity buses, while not painted yellow, are fitted with the similar interiors as well as the same traffic control devices for dropping off students (at other schools).

In the past, groups transporting children and adults that did not need (or afford) a large bus commonly used 15-passenger vans to handle their transportation. However, such vehicles were at a disadvantage by comparison in terms of meeting safety regulations. To provide an alternative to 15-passenger vans (called "non-conforming vans" because they do not meet any safety standards for school buses),^[31] bus manufacturers have designed vehicles as alternatives to 15-passenger vans. These are called Multi-Function School Activity Buses (MFSAB). The basic design of MFSABs differs from yellow school buses because of their intended use. As they are intended for point-to-point transportation instead of route service, MFSABs are not fitted with traffic control devices (i.e., red warning lights, stop arm) nor are they painted school bus yellow.^[32] MFSAB buses are typically based on Type A school buses, although manufacturers offer MFSAB configurations for full-size buses as well.

For educational use, MFSABs are primarily used for extracurricular activities requiring transportation; in the private sector, they are typically purchased by child-care centers.

Visibility

The vision field of a school bus crossview mirror; it allows the bus driver to observe blind spots close to the vehicle.

This is an inside view of a school bus that shows the many safety features of school buses, including several mirrors and built in sun visor.

A 1939 school bus seen in a museum display. Its orange color predates the adoption of school bus yellow.

Reflective tape on school buses (brightened by camera flash)

A key priority for a bus driver when driving, as well as when loading and unloading students, is proper sightlines around their vehicle; the blind spots formed by the school bus can be a significant risk to bus drivers and traffic as well as pedestrians. In the United States, approximately ⅔ of students killed outside of the school bus are not struck by other vehicles, but by their own bus.^[36]

To combat this problem, school buses are specified with sophisticated and comprehensive mirror systems. In redesigns of school bus bodies, driver visibility and overall sightlines have become important considerations. In comparison to school buses from the 1980s, school buses from the 2000s have much larger windscreens and fewer blind spots.

Traffic priority

By the mid-1940s, most states had traffic laws requiring motorists to stop for school buses while children were loading or unloading. The justifications for this protocol are:

• Children, especially the younger ones, have normally not yet developed the mental capacity to fully comprehend the hazards and consequences of street-crossing, and under U.S. tort laws, a child cannot legally be held accountable for negligence. For the same reason, adult crossing guards often are deployed in walking zones between homes and schools.
• It is impractical in many cases to avoid children crossing the traveled portions of roadways after leaving a school bus or to have an adult accompany them.
• The size of a school bus generally limits visibility for both the children and motorists during loading and unloading.

Since at least the mid-1970s, all U.S. states and Canadian provinces and territories have some sort of school bus traffic stop law; although each jurisdiction requires traffic to stop for a school bus loading and unloading passengers, different jurisdictions have different requirements of when to stop. Outside of North America, the school bus stopping traffic to unload and load children is not provided for. Instead of being given traffic priority, fellow drivers are encouraged to drive with extra caution around school buses.

Warning lights and stop arms

School bus using amber 8-way warning lights

Closeup of deployed stop arm

Around 1946, the first system of traffic warning signal lights on school buses was used in Virginia. This system comprised a pair of sealed beam lights similar to those employed in American headlamps of the time. Instead of colorless glass lenses, the warning lights utilized red lenses. A motorized rotary switch applied power alternately to the red lights mounted at the left and right of the front and rear of the bus, creating a wig-wag effect. Activation was typically through a mechanical switch attached to the door control. However, on some buses (such as Gillig's Transit Coach models and the Kenworth-Pacific School Coach) activation of the roof warning lamp system was through the use of a pressure-sensitive switch on a manually controlled stop paddle lever located to the left of the driver's seat below the window. Whenever the pressure was relieved by extending the stop paddle, the electric current was activated to the relay. Plastic lenses for warning lights were developed in the 1950s, though sealed beams—now with colorless glass lenses — were still most commonly used behind them until the mid-2000s, when light-emitting diodes (LEDs) began supplanting the sealed beams.

With the adoption of FMVSS 108 in January 1968, four additional warning lights were gradually added to school buses; these were amber in color and mounted inboard of the red warning lights.^[41] Intended to signal an upcoming stop to drivers, as the entry door was opened at the stop, they were wired to be overridden by the red lights and the stop sign.^[41] Although 8-light systems were adopted by many states and provinces during the 1970s and 1980s, the all-red systems remain in use by some locales such as Saskatchewan and Ontario, Canada, as well as on buses built in Wisconsin before 2005 ^[42] and older buses in California.

To aid visibility of the bus in inclement weather, school districts and school bus operators add flashing strobe lights to the roof of the bus. Some states (for example, Illinois)^[43] require strobe lights as part of their local specifications.

During the early 1950s, states began to specify a mechanical stop signal arm which the driver would swing out from the left side of the bus to warn traffic of a stop in progress. The portion of the stop arm protruding in front of traffic was initially a trapezoidal shape with stop painted on it. The U.S. National Highway Traffic Safety Administration's Federal Motor Vehicle Safety Standard No. 131 regulates the specifications of the stop arm as a double-faced regulation octagonal red stop sign at least 45 cm (17.7 in) across, with white border and uppercase legend. It must be retroreflective and/or equipped with alternately flashing red lights. As an alternative, the stop legend itself may also flash; this is commonly achieved with red LEDs.^[44] FMVSS 131 stipulates that the stop signal arm be installed on the left side of the bus, and placed so that when it is extended, the arm is perpendicular to the side of the bus, with the top edge of the sign parallel to and within 6 inches (15 cm) of a horizontal plane tangent to the bottom edge of the first passenger window frame behind the driver's window, and that the vertical center of the stop signal arm must be no more than 9 inches (23 cm) from the side of the bus. One stop signal arm is required; a second may also be installed.^[44] The second stop arm, when it is present, is usually mounted near the rear of the bus, and is not permitted to bear a stop or any other legend on the side facing forward when deployed.^[44]

The Canadian standard defined in Canada Motor Vehicle Safety Standard No. 131, is substantially identical to the U.S. standard.^[45]

Safety devices

Typical school bus rear emergency exit door

School bus with its crossing arm deployed at a bus stop

In addition to the warning devices that allow them to stop traffic around them when picking up or dropping off students, school buses are also equipped with a number of different safety devices to prevent accidents or injuries and for the purposes of security.

Compartmentalization

School bus seats (rear view). Part of the premise behind compartmentalization is close spacing of each set of seats.

In 1967 and 1972, as part of an effort to improve crash protection in school buses, researchers at UCLA would play a role in the development of the interior design for school buses that was phased in by the end of the 1970s. Using the metal-backed seats then in use as a means of comparison, several new seat designs were tested. In its conclusion, the UCLA researchers found that the safest design was a 28-inch high padded seatback spaced a maximum of 24 inches apart, using the concept of compartmentalization as a passive restraint.^[56] While the UCLA researchers found the compartmentalized seats to be the safest design, they found active restraints (such as seatbelts) to be next in terms of importance of passenger safety.^[56]

In 1977, FMVSS 222 mandated a change to compartmentalized seats, though the height requirement was lowered to 24 inches.^[50]

According to the NTSB, the main disadvantage of the design is its lack of protection in side-impact collisions (with larger vehicles) and rollover situations.^[56] Though by design, students are protected front to back by compartmentalization, it allows the potential for ejection in other crash situations (however rare).^[56]

Alternative fuels

A Blue Bird Vision equipped with a propane fuel system.

Although diesel fuel is most commonly used in large school buses (and even in many smaller ones), alternatives such as LPG/propane and CNG have been developed to counter the drawbacks that diesel and gasoline-fueled school buses pose to the public health and environment.

The use of propane as a fuel for school buses began in the 1970s, largely as a response to the 1970s energy crisis. Initially produced as conversions of gasoline engines (as both require spark ignition), propane fell out of favor in the 1980s as fuel prices stabilized, coupled with the wider usage of diesel engines. In the late 2000s, propane-fueled powertrains reentered production, as emissions regulations began to negatively affect the performance of diesel engines. In 2009, Blue Bird Corporation introduced a version of the Blue Bird Vision powered by a LPG-fuel engine.^[61] As of 2018, three manufacturers offer a propane-fuel full-size school bus (Blue Bird, IC, and Thomas), along with Ford and General Motors Type A chassis.

Compressed natural gas was first introduced for school buses in the early 1990s (with Blue Bird building its first CNG bus in 1991 and Thomas building its first in 1993)^[61][62] As of 2018, CNG is offered by two full-size bus manufacturers (Blue Bird, Thomas) along with Ford and General Motors Type A chassis.^[61][63]

Electric school buses

In theory, urban and suburban routes prove advantageous for the use of an electric bus; charging can be achieved before and after the bus is transporting students (when the bus is parked). In the early 1990s, several prototype models of battery-powered buses were developed as conversions of existing school buses; these were built primarily for research purposes.

During the 2000s, school bus electrification shifted towards the development of diesel-electric hybrid school buses. Intended as a means to minimize engine idling while loading/unloading passengers and increasing diesel fuel economy^[64], hybrid school buses failed to gain widespread acceptance. A key factor in their market failure was their high price (nearly twice the price of a standard diesel school bus) to and hybrid system complexity.^[65]

In the 2010s, several fully electric school buses would enter the marketplace. Trans Tech Bus would produce two designs, the eTrans (based on the Smith Electric Newton cabover truck),^[66] and the SST-e, a conversion of the Ford E-Series. Lion Bus introduced the eLion conventional, the first full-size electric school bus, in 2015. In 2017, several manufacturers added electric school buses to their product ranges, with electric versions of the Blue Bird All American, Blue Bird Vision, Micro Bird G5 on ford E450 Chassis, IC CE-Series, and Thomas Saf-T-Liner C2 making their debut for future production.

In law enforcement

Blue Bird Mobile Command Unit operated by the NYPD.

Larger police agencies may own their own police buses for a number of purposes derived from school bus bodies. Along with buses with high-capacity seating serving as officer transports (in large scale deployments), other vehicles derived from buses may have little seating, serving as temporary mobile command centers; these vehicles are built from school bus bodyshells and fitted with agency-specified equipment.

Prisoner transport vehicles are high-security vehicles used to transport prisoners; a school bus bodyshell is fitted with a specially designed interior and exterior with secure windows and doors.

In community outreach

Bookmobile operated by New Orleans Public Library

Church buses in Memphis, Tennessee

In terms of vehicles used for community outreach, school bus bodyshells (both new and second-hand) see use as bookmobiles and mobile blood donation centers (bloodmobiles), among other uses. Bookmobiles feature interior shelving for books and library equipment; bloodmobiles feature mobile phlebotomy stations and blood storage.

Both types of vehicles spend long periods of time parked in the same place; to reduce fuel consumption, they often have on-board electrical generators to power their interior equipment and climate control.

In church use

Churches throughout the United States and Canada use buses to transport their members, both to church services and to church events. In this capacity, many churches use vehicles based on school buses. Some churches own school buses purchased second-hand, while other churches own vehicles purchased new (other churches own minibuses with wheelchair lifts).

In nearly all cases, federal regulations require the removal of "School Bus" lettering and the disabling/removal of stop arms/warning lights.^[2] In some states, the bus is required to change its color from School Bus Yellow entirely. In church use, transporting adults and/or children, traffic law no longer gives church buses traffic priority in most states (Alabama, Arkansas, Kentucky, Tennessee, and Virginia being the only states where a church bus can stop traffic with flashing red lights^[67]).

Uses of retired school buses

As of 2016, the average age of a school bus in the United States is 9.3 years.^[68] School buses can be retired from service due to a number of factors, including vehicle age or mileage, mechanical condition, emissions compliance, or any combination of these factors.^[68] In some states and provinces, school bus retirement comes is called for at specific age or mileage intervals, regardless of mechanical condition. In recent years, budget concerns in many publicly funded school districts have necessitated that school buses be kept in service longer.

When a school bus is retired from school use, it can see a wide variety of usage. While a majority are scrapped for parts and recycling (a requirement in some states), better-running examples are put up for sale as surplus vehicles. Second-hand school buses are sold to such entities as churches, resorts or summer camps; others are exported to Central America, South America, or elsewhere. Other examples of retired school buses are preserved and restored by collectors and bus enthusiasts; collectors and museums have an interest in older and rarer models. Additionally, restored school buses appear alongside other period vehicles in television or film.

After a school bus is sold, NHTSA regulations require that the stop arms and warning signals of a school bus be removed or disabled.^[2] If the bus is to transport passengers, the exterior must be painted a color other than school bus yellow and all school bus lettering must be removed.^[2]

School bus conversions

1980s Wayne Lifeguard school bus converted to RV (with Volkswagen Vanagon on roof)

In retirement, not all school buses live on as transport vehicles. In contrast, the purchasers of school buses use the large body and chassis to use as either a working vehicle, or as a basis to build a rolling home. To build a utility vehicle for farms, owners often remove much of the roof and sides, creating a large flatbed or open-bed truck for hauling hay. Other farms use unconverted, re-painted, school buses to transport their workforce.

Skoolies are retired school buses converted into recreational vehicles (the term also applies to their owners and enthusiasts). While some examples are fairly primitive, others rival production-built RVs in equipment and quality. Exteriors can range from conservative designs to the bus equivalent of an art car.

An example of a school bus converted to an RV is the 1946 International Harvester school bus abandoned on the Stampede Trail in Alaska where Christopher McCandless lived and died in 1992 (often referred to as the "Magic School Bus").

School bus export

Retired school buses from Canada and the United States are sometimes exported to Africa, Central America, South America, or elsewhere. Used as public transportation between communities, these buses are nicknamed "chicken buses" for both their crowded accommodation and the (occasional) transportation of livestock alongside passengers. To attract passengers (and fares), yellow buses are often repainted with flamboyant exterior color schemes and modified with chrome exterior trim.