Manufacturers do not always think through the scenarios that purchasers of their products are likely to encounter at the operating level. Nor do the purchasers. Sometimes the quirks can be mystifying. But ineffective responses to these quirks can lead to serious incidents, injuries and damage awards.
Lift Platforms and Bean Stalks
If a wheelchair fits on a lift platform on the way up, it should fit on the way down, right? Not always:
A passenger wheeled her 50-inch-long electric scooter onto the lift platform, the driver raised it to the floor level, and the occupant motored the scooter into a securement location. When the bus reached her destination, the driver walked to the rear, un-stowed the lift platform, and the occupant drove onto it, facing outward, as appropriate. When the platform began to descend, both the driver and passenger immediately heard a “scraping sound.” Noticing the rear of the scooter “hung up” on the floor surface, the driver stopped the platform’s descent, returned it to the floor level, and told the occupant, “I’ll fix it.”
What happened next is unclear. The driver may have pulled out a knob on the scooter’s rear housing, releasing the scooter’s “passive” brakes, and placing it in “roll mode.” Or he may simply have pushed the scooter forward with its brakes still engaged. In either case, he tried to squeeze the scooter onto the now-too-short lift platform. (After all, d’uh, it fit going up!) Because this relatively old bus’ lift platform contained an obsolete, oblique outer lip, the driver’s efforts quickly overcame the lip’s resistance, and the scooter and its occupant sailed off the end of the platform. So great were the forces of his shove compared to the resistance of the lip that the momentum also jettisoned the driver off the platform along with them.
Levers and Fulcrums
As a matter of leverage, the higher up on the hinged lip one applied a force, the less force it took to depress it. Because either the forward edge of the scooter’s housing intersected the lip’s surface at a point roughly 8 inches from its inner edge, I measured the forces it would take to depress the lip at various points, in 1 ½-inch increments, to be:
|9.0 inches from lower edge||10.75 lbs|
|7.5 inches from lower edge||22.50 lbs.|
|6.0 inches from lower edge||31.85 lbs.|
I was unable to test the forces needed at 4.5 inches because I was simply not strong enough, given the awkward, kneeling position I had to take to push against it (there was nothing to which I could hook the force gauge so that I could pull the lip down while standing outside the bus).
I then measured the forces needed to simply move the scooter:
- In “roll mode,” I measured the forced needed to push it forward to be roughly seven pounds.
- With its passive brakes engaged, the forces needed were closer to 40 pounds – although my measurements were a bit quirky since, in the process, I felt myself approaching hernia status.
From this analysis, I calculated the combined forces needed for the only two plausible incident scenarios I could think of:
- If the driver had released the scooter’s “passive brakes,” the forces needed to begin depressing the lip equaled (a) the forces needed to depress the lip, plus (b) the forces needed to roll the scooter forward.
- If the driver had not released the passive brakes, the forces needed to begin depressing the lip equaled (a) the forced needed to depress it plus (b) the forces needed to push the scooter forward with its brakes engaged.
Regardless of which scenario had occurred, it was clear that, with a combined force of roughly 25 pounds (in “roll mode”) or 50 pounds (in “brake mode”), the driver managed to overcome the resistance of the lip with enough inertia left over to propel both himself and the scooter-and-occupant overboard.
Riddles and Curiosity
On the witness stand, the driver freely admitted pushing the occupant and her scooter off the platform, and flying off after them. Had he not admitted this, he would have been faced with the task of explaining what his “fix” could possibly have involved, since:
- He could not alter the length of the plaintiff’s scooter
- He could not alter the length of the lift platform
- He did not stow and redeploy the platform
- He did not perform any maintenance on the lift mechanism
- The platform controls permitted only a single sequence of deployment, lowering and lip depression
- He had no access to any additional lift mechanism controls
- He could not alter the angle of the platform’s outer lip
- He could not alter the resistance of the lip
What this clever driver failed to recognize, of course, was that once he began to depress the lip, it then required increasingly less force to continue doing so as the scooter proceeded forward, with the lip declining toward the horizontal. As a result, his huff-and-a-puff not only blew the house down, but carried him along with it.
I am always curious about the reasons why accidents and incidents happen – even when they appear to reflect little more than garden-variety ignorance or a lack of proper training. It is particularly important to explore whether or not a driver’s or witness’ account is even plausible, compared to being simply a tall tale. So I was curious about how the scooter in this incident could have fit onto the platform only during the boarding process. The answer lay in the hinge between the platform and the bus floor:
- At the ground level, the hinge configured itself as an inch-and-a-half-wide horizontal band adjacent to the platform, effectively increasing the platform’s length.
- At the floor position, this hinge was configured vertically, rendering the platform length shorter.
Not knowing any of this hardly excused the driver for trying to squeeze the passenger’s scooter onto the lift platform (although he could have asked her to try to power it as far forward as it would go). But it helped to explain it.
Hassles and Harbingers
Oversized wheelchairs have posed an enigma to the transit industry since the initial requirements for wheelchair lifts were enacted in 1976, under the doctrine of “full accessibility” (a requirement reversed by the Reagan administration in 1980, only to be reversed yet again in 1991 when the Americans with Disabilities Act was promulgated). There have been class action suits related to this issue (the most famous being Keirnan v. Utah Transit Authority). And some unusual incidents entered transit industry folklore: In the early days of ADA compliance, one oversized gentleman whose combined 900-lb. personage-plus-electric-wheelchair exceeded the 600-lb. capacity of most bus lifts of that era delighted in staging episodes of “trip denial” for his local media and press. Most recently, the FTA has considered changing platform dimension requirements to exceed the current minimum of 30 x 48 inches in order to accommodate oversized wheelchairs.
As a practical matter, every transit agency (or transit operation directed by other lead agencies) must provide complementary paratransit service to disabled individuals (unless the system serving the general public is already provided on a demand-responsive basis). A practical response to the occasional, oversized wheelchair challenge would be to simply purchase a paratransit vehicle with an oversized lift, and instruct fixed route bus drivers to summon one (via their dispatchers) whenever they come upon a wheelchair or scooter too large their bus’ standard lift platform.
Such thinking, of course, is anathema to U.S. transit agencies which, almost universally, try to control paratransit service delivery costs by limiting access to service (rather than by improving productivity). Of course, when the inevitable class action lawsuits catch up to them, the Consent Decrees devised to settle these disputes typically include provisions to dispatch a paratransit vehicle whenever a fixed route bus cannot accommodate a wheelchair occupant for other reasons (e.g., the lift mechanism is not working, the bus is too overcrowded, etc.). Rather than employ this solution to accommodate oversized wheelchairs – “connecting the dots” that already exist – the transit industry may choose instead to enlarge the lift platforms of its entire fleet.
At the present time, of course, someone with a wheelchair or scooter too large to occupy a lift platform can simply be denied service. It is a shame, from an economic perspective, that solutions between these two extremes have rarely if ever been considered. Regardless, trailing a decade behind the transit industry in ADA compliance yet without its own network of “complementary paratransit services,” the motorcoach industry may soon find itself burdened with larger lift platforms. More weight, more engineering changes, more opportunities for structural deformation, lower fuel efficiency. Just what we need.
Feedback, Fables and Fortunetelling
The long-range solution to the incident described above is, of course, to maintain a process whereby drivers convey information about on-the-road equipment and operating problems to supervisors, supervisors pass them along to problem-solvers, and problem-solvers resolve them. Given the size of the transit system involved in this particular incident, the situation confronted by the driver-in-question should have led to an operating solution long before this episode occurred. In contrast, that agency’s management is in such disarray (or denial) that, in a recent deposition (on a different case involving a different set of issues), one of its mechanics testified that he had never once heard of an incident of any kind involving a wheelchair lift deficiency during his entire 24 year career of service. (That same witness testified that he had also never heard of a lawsuit involving a door malfunction – although I myself have been engaged in four door-related lawsuits involving his transit agency.)
Our childhoods were enriched with the fable of a small Dutch boy who saved Amsterdam by sticking his finger in a hole in the dike. The larger lesson in life is that one must first look for the holes. If your management fails to do this, that trickle of lawsuits siphoning off your operating budget may soon become a flood.