Update on School Bus Safety Belts
The question keeps coming up: Should school buses have seat belts? School officials, school
bus manufacturers, researchers, accident investigators, parents (and grandparents) of
school-age children are seeking answers. Answers vary because the question involves
complicated engineering, biomechanical and behavioral issues.
In 1987 the National Transportation Safety Board (NTSB) published a study based on detailed
investigations of 43 serious accidents involving large school buses that occurred between
1983 and 1986.(1) One of NTSB's conclusions was that lapbelts probably would have had no
effect on the 13 passenger deaths in the crashes studied and that, had they been used, an
additional death might have occurred. Other conclusions were that lapbelt use: a) probably
would have worsened the outcome for one-fifth of passengers who received moderate
injuries; and b) would not have reduced minor injuries.
If such conclusions seem unreal, remember that since 1977 large school bus manufacture
must meet several Fed-Motor Vehicle Safety Standards (FMVSS).(2) The purpose of
Standard No. 222 on seating and crash protection is "to reduce the number of deaths and the
severity of injuries that result from the impact of school bus occupants against structures
within the vehicle during crashes and sudden driving maneuvers." The basic requirements of
this standard -- stronger seats that are closer together (24 inches or less), better anchored to
the floor, well-padded to absorb energy upon impact, and have higher seatbacks (at least 20
inches) but no seat belts --provide a high degree of protection for children transported in
today's large school buses.
The collective term for these school bus seating features is "compartmentalization." This
explains why, in its study of serious accidents, NTSB found that passengers in large school
buses would, overall, receive no net benefit from lapbelt use. In reaching this conclusion,
NTSB reported that it did not consider the possibility of lapbelt-induced injuries and, had it
done so, the overall net effect of lapbelts would have been negative for large school buses.
The reason: in crashes of high impact, lapbelted passengers often receive serious, even fatal,
injuries from being violently forced against the belts, a fact well-documented in automobile
crashes.
In a 1986 study, NTSB referenced more than 100 cases from medical literature on
lapbelt-induced injuries in automobile crashes. Often, these difficult-to-diagnose injuries are
not discovered for hours, even days, after the crash. In light of known deficiencies of
lapbelt-only systems, NTSB urged action "to reduce reliance on lapbelts and increase the
availability of lap-shoulder belt systems."(3) Rather than recommending add-on shoulder
belts, NTSB advised integrated, continuous loop, self-storing lap-shoulder belt systems to
replace lapbelts entirely.
I also reviewed NTSB's findings in an investigation of 43 accidents involving large
post-standard school buses. My conclusion from the evidence presented in that study was
that "large school buses do not need and should not have seat belts -- except for the
drivers."(4)
In a study of school bus seat belts conducted for the California Highway Patrol, the research
team concluded, "We believe existing research, testing, and accident statistics weigh against
new lapbelt policies for Type I (large post-standard) school buses when taking into
consideration accident mode probabilities and a factor for average severity in each accident
mode."(5)
Although large school buses comprise nearly 85 percent of the nation's school bus fleet, many
children are transported each school day in small school buses and in van conversions. The
capacity of these vehicles generally ranges from 11 to 23 passengers. Included are
specialized vehicles for carrying physically and mentally disabled children, some in
wheelchairs. Despite their small size, most of these vehicles look like school buses. They are
painted National School Bus Glossy Yellow, have the words SCHOOL BUS front and rear, and
are equipped with flashing lights used to signal motorists when the bus is about to stop or is
stopped to load or unload passengers.(6) Add to these unique characteristics the fact that all
school buses run with headlights on, and the presence (in nearly half the states) of a STOP
signal arm that swings out from the left side while the bus is stopped for loading/unloading,
and one has to wonder how anyone could fail to recognize a stopped school bus regardless of
its size.
Study of small bus crashes
To round out its investigation of school buses performance in severe accidents, NTSB studied
24 small school bus crashes that occurred between 1983 and 1988.(7) These vehicles were
manufactured after April 1, 1977. On this date two other standards affecting all school buses
became effective (in addition to the seating standard previously discussed). These FMVSS are
No. 220 -- School Bus Rollover Protection and No. 221 -- School Bus Body Joint Strength.(8)
Single-vehicle and multiple-vehicle crashes, side and rear-end collisions (sometimes followed
by rollover), and non-collision rollovers were among the investigated accidents.
It should be noted that among the FMVSS affecting school buses, seating requirements differ
substantially for large (more than 10,000 lbs. gross vehicle weight rating (GVWR), which
includes the vehicle and its load) and small (10,000 lbs. GVWR or less) school buses. Instead
of the previously described compartmentalized seating (without lapbelts) for large school
buses, federal standards allow seats in small school buses to be spaced as desired and
require a lapbelt at every occupant seating position.(9)
Using criteria comparable to those applied in its earlier study, NTSB included small school bus
accidents in its study only if the case vehicle was occupied primarily by preschool or
school-age children, and if one of these conditions was met: a) the vehicle had to be towed
from the accident scene; b) the vehicle overturned; or c) at least one passenger was seriously
injured or killed. These accident criteria allowed NTSB "to examine the crash performance of
small school buses in accidents that put the occupants at risk of injury."(10) (Note: This
review centers on the outcomes of 24 accidents involving small school buses manufactured to
FMVSS. Four other cases involving small school vehicles (van conversions) not built to federal
standards were included in the NTSB study.
Classifying injuries
As in its earlier study, NTSB obtained detailed information about each injured person through
interviews with surviving occupants, parents, school officials and medical personnel, and
through reviewing available hospital records.
In both studies, NTSB classified all injuries using the Abbreviated Injury Scale (AIS) originally
developed by a Joint Committee on Injury Scaling, representing the American Medical Assn.,
American Assn. for Automotive Medicine and Society of Automotive Engineers.(11) The AIS is
employed by a variety of traffic crash investigators and researched in both the U.S. and other
countries. Investigators undergo training in using the scale, learning how to distinguish
between an injury (which is coded) and its outcome (not coded), and becoming familiar with
detailed medical terminology used to identify injuries and assign appropriate codes.
The basic purposes behind development of AIS were: "1) to produce a scale that would
facilitate uniform data bases for statistical evaluation among investigators anywhere in the
world; and 2) to standardize the language used to describe injuries."(12) Refined over the
years, AIS now includes the severity codes shown in Table 1.
In its study of small school bus accidents, NTSB found that of the 167 passengers (including
six aides) in these accidents, 145 (86.8 percent) were not injured or received only minor
injuries. This percentage is close to the 90 percent of 1,119 passengers (without lapbelts)
who were uninjured or received only minor injuries in the 43 severe accidents involving large
school buses.(13)
Different standards for different school buses
In the FMVSS that took effect in early 1977, the National Highway Traffic Safety
Administration (NHTSA) differentiated between large and small school buses because, in
similar collisions, the crash pulse experienced by small vehicles is more severe than for larger
vehicles.(14) Beyond differences in the standards for rollover protection and strength of body
panel joints, seating standards are what differentiate small school buses from large ones.
Instead of the highly protective, compartmentalized arrangement, seats in small school
buses can be spaced as desired, and a lapbelt is required at every occupant seating position.
Further, small school bus standards do not require restraining barriers in front of the first
rows of seats; these are mandated for large school buses.
What did NTSB find in the 24 small school bus crashes investigated? Did the seat belts
perform well? In this study, the complete details of each case were described in narrative
form, followed by a diagram showing occupant seating positions, use of restraints and
injuries sustained. Figure 1 illustrates the type of diagram used. A listing of occupants by sex,
age, seating locations and maximum injury by AIS codes accompanied each diagram.
Twenty of the 24 drivers were restrained when the accidents occurred -- 11 in lapbelts and
nine in lap-shoulder belts. Of the six aides, two wore lapbelts and four were unrestrained.
(Table 2)
Table 3 shows, by case number, bus capacity, number of passengers, and distribution of
passenger injuries by severity. The only occupants who received fatal injuries (Case No. 17)
were two boys (ages seven and 17) in the right front bench seat of a small school bus. The
bus was struck by an overturning truck. This head-on collision, followed by a secondary
impact on the left side of the bus as the truck rotated counterclockwise, was quite severe. The
17-year-old, seated next to the window, was wearing a lapbelt; the seven-year-old was
unrestrained.
Although aides share with drivers the task of making sure passengers are properly restrained,
four of the six aides were not belted; only 33 of their 46 charges -- preschoolers and special
education students (learning disabled, emotionally disturbed and physically disabled) ages
three to 21 -- were restrained. (Small school buses are commonly used to transport special
education students.)
Table 4 shows how many students were aboard, age ranges, the number restrained by
lapbelts, and the restraint status of the 24 drivers and six aides. All students were
unrestrained in Case Nos. 2, 4, 8 and 12. In these four cases, three of the drivers were also
unrestrained even though "nearly all states and local school districts have statutes or
regulations requiring the school bus drivers to be restrained when the bus is in motion."(15)
Lapbelt design
"Nearly all belts installed for passengers on school buses are 'static' lapbelts, the type
commonly found in airplanes and the center seating position of cars. Static belts are not
equipped with retractors that automatically tighten the belt around the occupant; instead,
the passenger must manually adjust the belts to ensure proper fit."(16) NTSB investigators
found this type of lapbelt was often worn loosely rather than snug and low on the abdomen.
A loose lapbelt exposes the wearer to abdominal and spinal injuries. It is easy to understand
why very young children and some special education students may not be able to wear this
type of lapbelt properly.
Once manufactured and equipped with occupant restraints that meet federal requirements,
lapbelts on small school buses undergo not only normal wear and tear. They are often
replaced by jury-rigged arrangements that do not meet original standards requirements. On
one bus, NTSB investigators found a mixture of belts, some with pushbutton release buckles,
others with lift-type releases. In another bus, webbing had been doubled over on two lapbelts,
holes punched through the folded-over webbing, and the belts bolted back onto the seat
frame; this was done to meet complaints that the belts did not fit small children. A particularly
egregious example of "homemade" restraints was the joining of two lapbelts to form one
restraint that would loop around two or three children on the same bench seat.
As co-principal investigator in a study performed for the U.S. Dept. of Transportation in 1967,
I saw several large school buses in a school district near Topeka, KS, with long belts mounted
to loop around three children on each front row seat. As reported in that study, "State school
authorities do not believe that pupil passengers should be required to wear seat belts." One
school transportation official commented that the "wide range of opinions and constant
publicity given to the desirability of using seat belts in school buses should be resolved."(17)
Nearly 25 years later, the matter is still unresolved.
In 1985, according to the Insurance Institute for Highway Safety (IIHS), 18 school districts
throughout the country required new school buses to be equipped with seatbelts.(18) To date,
New York is "the only state to require that all new school buses, regardless of size, be
equipped with lapbelts for passengers."(19)
A 1988 survey conducted in New York school districts with formal policies mandating seatbelt
use found that fewer than 25 percent of students on belt-equipped buses wore them. The
lapbelts on some buses had been vandalized -- buckles removed, buckles broken or belts tied
together. According to the survey, repair and replacement costs, plus labor and vehicle
downtime, were projected to exceed $1 million per year statewide. A year later, another
survey revealed that lapbelts can cause injuries in noncrash situations -- such as from the
belts being used as weapons or to trip passengers.(20)
Restraining barriers
In 1987 Congress requested the National Academy of Sciences to investigate the causes of
fatalities and injuries to school children riding in school buses, the use of seat belts in school
buses, and other measures that could improve the safety of school bus transportation.(21)
Utilizing a committee of specialists from relevant fields, the Academy "reviewed hundreds of
study reports, accident analyses, and technical articles to evaluate the likely effectiveness of
measures that might improve the safety of school bus transportation. . . . Much of the study
effort was devoted to seat belts and other approaches to occupant restraint."(22)
At the end of this in-depth study, most committee members believed "that states and local
school districts should not be encouraged to equip new buses with seat belts." Some
members took the opposite view, however, based upon the desirability of "a uniform
occupant-restraint policy for all motor vehicles"(23)
Among several presentations before the committee were ones made by representatives of
NHTSA, NTSB and the National Coalition for Seatbelts on School Buses (NCSSB). Formed in
1984, the NCSSB states that the need for seat belts on school buses has been endorsed by
several medically oriented groups such as the American Medical Assn., and asks, "Why are
children, accustomed to riding buckled up in the family car, being denied the right to this
extra margin of protection on the school bus?"(24)
Other views
The IIHS report mentioned earlier focused on school buses and seat belts. A major concern
was the contradiction between efforts to persuade children to fasten seat belts in cars when
their school buses have no belts. A NHTSA official was quoted as saying, "It's a very awkward
situation. We can't really argue with the concept of establishing better belt habits in children."
The official noted, however, that the possibility of exacerbating head injuries in frontal
impacts made the agency reluctant to endorse seatbelts for school buses. In the same report,
an orthopedist who had worked to promote seat belts in New York recognized that large
school buses are already very safe vehicles, but admitted that "we're out to save lives in the
car." Along with others holding the same view, he said it is confusing to tell children that belts
are a good thing in cars but are not necessary in school buses.(25)
Counter arguments
Parents, teachers and traffic safety specialists could strive harder to explain the rationale for
seatbelts being in cars but not in large school buses. There are no seatbelts (except for the
driver) in transit buses that carry riders to and from work, shopping, and for other purposes
-- including transporting school children -- in urban areas nationwide. There are no seatbelts
in Amtrak passenger cars, nor in commuter trains or streetcars. There are no seatbelts
(except for the driver) in charter and tour buses, nor in over-the-road buses carrying
passengers from city to city.
Today's large school buses, in which seating meets exacting standards, are not equipped with
seatbelts (except for the driver). From every aspect of design, seating provides a very
protective environment for the millions of children and youth riding to and from school every
day.
In today's small school buses --those initially built to federal standards that require at least a
lapbelt at every seating position -- increased effort needs to be directed to: a) making sure
that drivers, aides and children habitually use seatbelts; and b) maintaining belts, buckles
and anchorages in first-rate condition throughout the 10 or more years these vehicles
typically remain in service.
With increased interest in school bus safety, we can expect continued efforts to develop
better seating systems in both small and large school buses -- with and without seat belts. In
fact, experiments have been conducted with padded "lap bars" as an alternative to lapbelts.
In one design, such a bar, accommodating one to three children on a bench seat, would be
pulled down by the occupants to protect them in frontal crashes. Other work undertaken in
Canada has tested lap-shoulder belts, as well as rear-facing seats with lapbelts.(26)
Tempering the discussion
During the heated exchanges that will ensue, remember these basic facts about the school
transportation system:
* Drivers are selected with care, given initial and refresher training, hold special licenses in
most states, and are supervised closely.
* Routes are well-planned, with attention given to the location of each bus stop.
* Loading and unloading procedures are discussed and reviewed periodically with riders.
* Emergency procedures are discussed with riders who benefit from periodic bus evacuation
drills.
* Buses operate principally in daylight hours, on weekdays, and at relatively lower speeds
than other highway traffic.
* Buses undergo periodic inspection and maintenance to ensure continued readiness for safe
operation.
* Drivers routinely conduct walk-around inspections of their buses to check signal lights, tires
and other equipment.
* The distinctive yellow color, plus other identifying features, makes school buses highly
visible to highway users.
* Buses of all sizes are designed and manufactured to exacting federal safety standards
based on years of research and testing.
* The vehicle code in every state contains specific provisions (based on the Uniform Vehicle
Code)(27), which were thoughtfully developed and refined to ensure the safe operation of
school buses on public streets, roads and highways.
* Local and state law enforcement personnel give school buses special attention to help
ensure safe passage between children's homes and schools.
* School-related activity trips by bus are planned and carried out with careful attention to
anticipated conditions.
* State and local school officials base school bus operations on consensus standards and
procedures developed in a series of voluntary national conferences on school transportation
held approximately every five years since 1939.(28) The most recent conference, attended
by 350 representatives from 49 states, convened for five days at Central Missouri State
University during May 1990. Refinements of, and additions to, the previous (1985)
conference recommendations appear in a report recently published by the National Safety
Council.(29)
The 1990 conference reaffirmed the views on seat belts expressed in 1985, recognizing again
that the "passive restraint system" (compartmentalization) in post-1977 large school buses
is superior to "the protection provided by seat belts," and discouraging "the mandatory
installation and use of seat belts in (large) school buses until such time that extensive and
scientific research proves them to be more effective in injury prevention than the existing
passive restraint systems."(30)
"Today, public and private schools and school districts operate about 390,000 school buses,
which travel nearly four billion miles to transport 25 million children to and from school and
school activities."(31) In 1987 only 14 school bus occupants (including drivers and aides)
died in school bus-related accidents, close to the average of 14.3 such deaths over the
six-year period 1982-1987.(32) As tragic as these deaths are, school bus transportation
remains the safest form of highway transportation in the U.S.
These statements, as positive as they are, do not signify that school bus transportation is so
safe that it needs no further thought. School bus operations are a human enterprise, carried
out in a public context where serious mistakes can and do occur. The only prudent course,
therefore, is to build on experience to create a better future and, meanwhile, to sustain every
aspect of school bus transportation at the safest possible level.
How significant the availability --and use -- of seatbelts will become for those riding school
buses in the future, only time will tell.
References
(1). National Transportation Safety Board. Safety Study: Crashworthiness of Large
Poststandard Schoolbuses (NTSB/SS-87/01), 1987.
(2). National Archives and Records Administration. Code of Federal Regulations. Title 49 -Transportation, Part 571.
(3). National Transportation Safety Board. Safety Study: Performance of Lap Belts in 26
Frontal Crashes (NTSB/SS-86/03), 1986.
(4). Abercrombie, Stanley A. "What! No Seat Belts in Schoolbuses?" Journal of Traffic Safety
Education, Oct. 1987, p. 6-7.
(5). Booz, Allen and Hamilton in association with E. A. Williams & Associates. School Bus Seat
Belt Study. Submitted to California Highway Patrol, Dec. 1, 1987, p. 87.
(6). U.S. Dept. of Transportation, National Highway Traffic Safety Administration. Highway
Safety Program Standard 17, Pupil Transportation Safety, 1973. (This and other highway
safety program standards are now guidelines for the states rather than federal
requirements.)
(7). National Transportation Safety Board. Safety Study: Crashworthiness of Small
Poststandard School Buses (NTSB/SS-89/02), 1989.
(8). National Archives Record Administration, Title 49 -- Transportation, Part 571.
(9). National Archives Record Administration, Title 49 -- Transportation, Part 571.
(10). National Transportation Safety Board, NTSB/SS-89/02.
(11). American Assn. for Automotive Medicine. The Abbreviated Injury Scale. Arlington
Heights, IL, 1985.
(12). Petruccelli, Elaine, John D. States and Lee N. Hames. "The Abbreviated Injury Scale:
Evolution, Usage and Future Adaptability," Accident Analysis and Prevention, Vol. 13: 29-35,
1981.
(13). National Transportation Safety Board, NTSB/SS-87/01.
(14). National Transportation Safety Board, NTSB/SS-89/02.
(15). National Transportation Safety Board, NTSB/SS-89/02.
(16). National Transportation Safety Board, NTSB/SS-89/02.
(17). National Commission on Safety Education, National Education Assn. Study of School
Bus Safety. Prepared for U.S. Dept. of Transportation under Contract FH-11-6525, 1967.
(18). Insurance Institute for Highway Safety. School Buses and Seat Belts. Special issue of
Status Report, May 11, 1985. Arlington, VA.
(19). National Transportation Safety Board, NTSB/SS-89/02.
(20). National Transportation Safety Board, NTSB/SS-89/02.
(21). U.S. Congress. Surface Transportation and Uniform Relocation Assistance Act of 1987.
Public Law 100-17, Section 204. Schoolbus Safety Measures.
(22). Transportation Research Board, National Research Council. Improving School Bus
Safety (Special Report 222), 1989. Washington, DC.
(23). Transportation Research Board, Special Report 222, 1989.
(24). National Coalition for Seatbelts on School Buses. Brochure, 1989. Skokie, IL.
(25). Insurance Institute for Highway Safety, School Buses and Seat Belts, 1985.
(26). Transportation Research Board, Special Report 222, 1989.
(27). National Committee on Uniform Traffic Laws and Ordinances. Uniform Vehicle Code,
revised 1987. Evanston, IL.
(28). Farmer, Ernest. Accent on Safety: A History of the National Conference on School
Transportation, 1939-1985. Nashville, TN: McQuiddy Press, 1989.
(29). National Safety Council (forthcoming). National Minimum Standard Guideline for School
Buses and Operations. Chicago, IL, 1991 revised edition. (Recommendations of the 11th
National Conference on School Transportation, May 13-18, 1990 at CMSU, Warrensburgh,
MO.)
(30). Telephone conversation (July 2, 1990) with Dwight R. Carlson, director of school
transportation, Iowa Dept. of Public Instruction and on-location chairman of 1990 National
Conference on School Transportation.
(31). U.S. Congress. Public Law 100-17, Section 204, 1987.
(32). U.S. Dept. of Transportation, National Highway Traffic Safety Administration. Fatal
Accident Reporting System 1987. Dec. 1988.
Stanley A. Abercrombie holds a B.A. degree from Dartmouth College and a Master's in
Education from New York University, where he was Assistant Teaching Fellow at the Center
for Safety Education, 1939-40. In 1970, he joined the U.S. Dept. of Transportation's NTSA,
serving in the Office of Alcohol Countermeasures until he transferred in 1972 to Region IX as
highway safety management specialist. Mr. Abercrombie, a member of the ASSE San
Francisco Chapter, chaired the 9th National Conference on Safety Education and compiled
and edited the ASSE publication, Dictionary of Terms Used in the Safety Profession.