Whatever Happened to Seat Compartmentalization

In the late 1970s, in response to another fatality accident (the trigger for safety-related innovation in America), the National Highway Traffic Safety Administration (NHTSA) mandated the installation of compartmentalized seating in school buses of every type and size.

Compartmentalized seating is a controlled response to the free-flight characteristics of an unbelted passenger when inertial and centrifugal forces are exerted on his or her body. When a passenger flies forward (e.g., from a head-on collision), the torso generally collides with the seat back in front, usually in a knee-torso-head-impact sequence. Compartmentalized seats control this movement through variations in the density of the foam at different parts of the seat back. Because one’s knee generally strikes the seat back first, the foam density in the lower part of the seat back helps absorb this impact to slow down the rest of the passenger’s torso flying forward. Less dense foam in the upper middle section of the seat back similarly slows the movement of the passenger’s arms and shoulders into the seat back’s head-impact zone. Finally an even softer cushioning at the top further decelerates the speed of the passenger’s head moving forward – a movement already slowed down by the previous two components noted.

With no need for seatbelt technology in large school buses demonstrated conclusively by the exploitation of catastrophic crashes, this community was able to fend off political demands for its installation on large school buses in 44 States. In contrast, the compartmentalized seating so effective in school buses of all types and sizes was actually made available to the motorcoach community, in roughly the mid-nineties, by Freedman Seating. Almost no OEM or coach purchaser was interested, and this seat model went largely unsold.

Interestingly, in the school bus community, the astonishing success of compartmentalized seated contributed to a negligible number of onboard passenger injuries apart from those occurring in catastrophic or near-catastrophic accidents, where some experts (and mostly non-experts) speculate that three-point seatbelts would have “made a difference.” One salient characteristic of compartmentalized seating is that the passengers need not do anything (other than remain in their seats) to make it work.

Yet curiously, after decades, compartmentalization in school bus seats is still incomplete – an admission by NHTSA for at least the past decade. More curiously, the task of completing this process is almost trivial compared to what has already been done: One need only add padded armrests (better yet partitions), increase seat back height or add cushioned headrests, and contour the seat cushions – with optional three-point seatbelt inserts (and heavier anchorages and seat back structures to support them) as options.

Puzzling Responses, Driving Forces

Interestingly, the school bus and motorcoach communities’ responses to compartmentalized seating, including seatbelts as a complement or substitute, were completely different:

School bus Community – Based largely on the effectiveness of compartmentalization, only six States, since 1989, have required the installation of seatbelts on their large school buses. Three States (New York, New Jersey and Florida) require the installation of lap-belts only – a technology that has been proven deadly with even compartmentalized, closely-spaced seats. And Florida mandated their installation immediately after NHTSA’s reaffirmation, in 2004, that lapbelts were dangerous for vehicles with close seat-spacing, an unnecessary risk for a vehicle of this mass.

There have been a number of catastrophic school bus accidents drawn to the community’s attention. Despite these occurrences, the school bus community, for the most part (mirroring NHTSA recommendations) has withstood the political pressure for the installation of seat belts from parents, medical advocacy groups with little knowledge of or interest in compartmentalization, and elected officials dragged into the fray by these groups. Usage is required in only one state (New Jersey). Interestingly, compartmentalized seating effectively created the ability of most states to resist the push for the installation of seat belts on large school buses. More interestingly, no agency or advocacy group has called for the completion of compartmentalization.

The Motorcoach Community – The motorcoach industry’s response to three-point seatbelt technology was driven, lemming-like, by the lawsuit associated with a single catastrophic motorcoach accident in 2008 (involving a 1998 coach not even made in the U.S.) and the needless capitulation to a $30M damage settlement by one OEM, and large sums sheepishly donated by two others large OEMS only implicated by significant errors in an NTSB study of the incident (see “Enough is Enough,” Parts 1 – 12, in NATIONAL BUS TRADER (April, 2013 – July, 2014). As a consequence, beginning in 2009, virtually every motorcoach manufacturer has installed three-point seatbelts on its coaches – and one seating supplier even combined this technology with compartmentalized seats. Lately, some operators have spoken of passenger complaints about this latter technology’s comfort.

In contrast, NHTSA regulations for the installation of three-point seatbelts on new motorcoaches – with no requirement for (much less any improvement of) compartmentalized seating – go into effect later in 2016. Unlike the State of Florida’s requirement for seat belts (lap belts, no less) in large school buses, no regulations will be require their usage on motorcoaches in any states. My own experiences as an expert witness in several catastrophic motorcoach collisions has been that, while adults may wear their seatbelts during day-time and early-evening, most remove them later to sleep in their seats. Worse, while the motorcoach community’s zeal to adopt seatbelts stemmed only from one manufacturer’s needless response to a lawsuit, this community’s adoption of three-point seatbelts ignored the value of compartmentalization – as did the recent NHTSA regulations requiring its installation.

The failure to jointly (a) “complete” compartmentalization, (b) increase the comfort of these seats, and (c) integrate them with (optional) three-point seatbelts has deprived both communities of the optimal safety solution. At the same time, all seat back technologies have a number of drawbacks, ranging from unpredictable consequences in certain collision scenarios (e.g., buses rolling over onto their roofs) to the added weight and cost of seat anchorages to handle the increased “loads” of bodies on the seats, and reinforced seat backs to similarly handle these loads. These changes have been estimated to add another 1500 lbs. to a full-size bus or motorcoach – and could continue to incur costs over the life-span of the vehicle in additional fuel consumption, air pollution, vehicle maintenance, and road maintenance (unless roughly six seating positions were removed to offset this increased weight).

Down our Throats, and Up Wherever

The result of all our “progress” has given us:

• A motorcoach industry with a technology it does not want – with high capital and operating costs, and the probable loss of seating capacity (should more states continue weighing motorcoaches on truck scales), and occasional “incomplete” installations of a proven technology that weighs and costs nothing.

• A school bus industry with the right, albeit incomplete technology (for its larger vehicles whose mass exponentially outweighs the downsides of excluding seatbelt technology) and the means to fend off unneeded, less-worthy (compared to compartmentalization) and costly technology in 44 of 50 States – consistent with the opinions of NHTSA.

In truth, because motorcoach service is an interstate phenomenon, the imposition of regulations on this industry was appropriate. But because school buses are state-and-local-funded animals, with vivid differences in vehicle requirements from state to state (with the exception of a few NHTSA requirements), NHTSA had an easier time refraining from regulating seatbelts on school buses.

In all this, one of the most pathological failures of both the school bus and motorcoach communities has been their complete disinterest in things going on one-another’s communities. This apathy has translated into a loss of opportunities to work together and learn from the experiences of one another’s transportation community. Given both the rarity of compartmentalized seating in the motorcoach industry, and the imposition of seating on large motorcoaches, all new motorcoaches will contain three-point seatbelts while all large school buses in six of the 50 states will. Noteworthy again is the fact that when seatbelts are most needed (i.e., during late-night segments of runs) they are the least often used. Beyond this dysfunctional irony, three of the six pro-seatbelt States have mandated the installation of seriously-dangerous lap-belts on their large school buses. Apparently when NHTSA talks, only half the states’ leaders listen.

Right All Along

The saddest part of this saga is that, until recently pressured by Congress to cow-tow to the wishes of Congress and its uber-enemy National Transportation Safety Board, NHTSA had been free to clarify its points about seat belts for all modes:

• Requiring installation, at all seating positions, for vehicles weighing less than 10,000 lbs. GVWR.

• Forcefully opposing the installation of lap-belts, particularly on vehicles with close seat-spacing (like school buses and motorcoaches which, unlike private automobiles, have far greater mass and far fewer chances of passenger ejection).

• Abstaining on the merits of installing three-point seatbelts on any large vehicle – an abstention that at least keeps the pro-belt political pressure at bay from scientific evidence and test results.

This pre-occupation with the enormous pressure to require the installation of seat belts has also coincided – directly or incidentally – with the failure to “complete” compartmentalization. Had NTSTA done this, in particular, it would have been prudent for NHTSA to mandate compartmentalized seating on motorcoaches – a technology with superior safety benefits and no costs at the capital (i.e., installation) level or operating level (in increased fuel and pollution, and perhaps a decrease in seating capacity).

I would never claim, as a blanket statement in print, that government does not work. But in the world of occupant safety on public transportation vehicles, government clearly does not work.

The opinions expressed in this article are that of the author and do not necessarily represent the opinions of NATIONAL BUS TRADER, Inc. or its staff and management.


Publications: National Bus Trader.