Hmm. Just a couple of boxes for this stop. Don't need to use the liftgate. I'll just hop up there...." Delivery drivers do this every day, but how easy or difficult is it for them to climb up and over the liftgate and into the truck to fetch those boxes?
Many liftgates are built with steps placed at the sides of their framework and with grab handles on the truck body. Some don't have these things, but maybe they should. If so, where exactly should steps and handles be placed? Likewise, cargo stacked on lowered gates can block the lights and reflectors now in place, reducing motorists' view of the truck and the guy working around it on dark nights. What supplemental lighting can be used?
These were subjects of task force sessions during the American Trucking Associations' Technology & Maintenance Council meeting in Tampa, Fla., in February.
Regarding steps, users and manufacturers of liftgates discussed the ins and outs of entry and egress and how to make it safe for drivers and helpers. The object is to write a TMC Recommended Practice for members to use in spec'ing new equipment, but it can't just say, "Here, here, and there." Some definitions and dimensions are needed.Research
Fortunately, work has been done on such matters. Larry Disque of Lehman Liftgates, who chairs this task force, found some pertinent information in the so-called Tilman handbook, more properly titled the "Human Factors Design Handbook," by Barry and Peggy Tilman. Research with real working people led the authors to describe how certain designs can ease the strain and lessen the risk of climbing onto and off of equipment.
Different size people need different dimensions for optimum performance, and of course their bodies vary greatly in stature and limb length. It's possible to place steps and handles where a range of people can use them. Thus designers consider the "percentile" measurements of humans, with small women and men being in the 5th percentile and medium to large folks in the 95th percentile.
Tilman research concluded that the first step should be no more than 24 inches above the ground and preferably closer to 18 inches. Applied to liftgates, which are at the very rear of trucks, angle of departure comes into play: When the front of the truck climbs a driveway apron, its rear end dips down and a low-hanging step can drag on the pavement. So 18 inches might be OK for a short truck, but the step can hit the pavement if a truck has a long overhang behind the rear axle. Do that a few times and the step will be bent, ground down and soon depart from the truck.
In such applications, 24 inches would be better, but that's a big step for a small person. "Why worry about them?" one attendee asked. "We don't hire people like that." Someone answered, "Because demographics are changing, and more women and Hispanic and Asian men who tend to be small are getting into truck driving. You don't want to shut them out with steps made for big people only."
But if the first step's height is set at 24 inches, where should the second step be - 18 inches above the first? Another 24 inches? Tilman research suggests it should be no less than 5 inches and no more than 24, said Disque. Ideally, though, the second and subsequent steps should be evenly spaced, as they are on stairways.
OK, if the second step is the middle one and the third and final step is the truck body's floor, make the second step midway between those two heights. Simple, right? No, because liftgate makers usually don't know how high that floor will be, reps pointed out. They make the liftgates and sell them to body manufacturers, who then install them. The floor height can vary by a foot or more, depending on the type of chassis it goes on. How can "evenly spaced" be determined?
Now we have a problem, many people agreed. Well, maybe steps can be shipped in pieces with the liftgate, and the body builder can appropriately install them. Most manufacturer reps were not comfortable with that suggestion. And it appeared that some of them preferred that no recommendations be written, because they didn't want to be held to standards that would prove to be impractical, even if they're recommendations rather than regulations.
The matter of legal liability was a big elephant apparently absent from the room, because nobody mentioned it until a reporter (me) brought it up. TMC has twice before tackled the idea of writing a recommended practice on steps and handles for trailers. Each time the effort was swatted down by attorneys sensitive to manufacturers' concerns: If a product doesn't adhere to a recommendation, even if the customer didn't want the extra equipment, the builder could be accused of negligence if somebody hurt himself trying to climb up or down.
Conversely, if conveniently placed steps and handles allowed someone - a kid or a drunk - to climb up and then fall off, he could be accused of making an attractive nuisance. Sometimes you can't win.
But Disque, the chairman, persisted. "Let's put something out there, then see where we are," he suggested. That something is 18 to 24 inches for the first step, and participants will talk some more about the next steps at the next meeting, in September in Raleigh, N.C.Flexibility needed
Some time after the meeting, one of those present, Bill Rector of SAF-Holland, summarized things: "There are so many variables. There is some standardization you can establish, but there are so many variations in what's built. A recommended practice would be good, provided you put some flexibility in it."
So it was with two other task forces aiming to improve the lighting and reflective markings applied to liftgates. One dealt with column- or rail-type liftgates and the other with body mounts, also called tuck-unders. These are machines with moving parts that sometimes change the position of lights and taping attached to them. Lights and reflectors can also be blocked by cargo sitting on lowered gates while trucks and trailers are parked at curbs.
At the Tampa meeting, members of these groups combined them into one because their work was largely redundant, according to Arnold Kowal of Maxon Lift, who became co-chairman of the new task force with Jack Wyatt of Waltco Hydraulic Liftgate. The members - manufacturer reps and fleet managers - will continue to work on a way to describe where to place lights, reflectors and retroreflective tape to supplement what's already required by federal regulations.
"It's a learning experience," said Kowal, who's also involved in the task force on liftgate steps.
"And it's definitely a challenge getting a consensus - not unanimous, but a consensus of feelings on the issues." So it will take another year of work - two more TMC meetings - before a recommended practice on lights and reflectors is written and distributed for balloting by TMC members.
Meanwhile, a dealer salesman in the West said he saw a "conspicuity enhancement kit" (or words to that effect) advertised, "So I thought I'd order it to see what it was, because it wasn't expensive.
"When it got here it turned out to be two orange (traffic) cones in a box."
From the July Issue of Heavy Duty Trucking