No. 22
How do bread tray dollies reduce labor time between truck unload and in-store floor merchandising?
- 7 sections
- 2 tables
A dolly saves time by turning many individual tray movements into a few rolling movements: instead of carrying trays two or three at a time from the truck to the shelf and back, the driver rolls a whole column and handles each tray once, at the shelf. How many minutes that saves depends on the store, so the number has to come from a time study on your own routes rather than from a published average. This guide shows where the time comes from, how to measure it, and the two limits that decide whether a store can take dolly delivery at all: stack height and door and aisle clearance.
Where the time goes without a dolly
List the movements for one stop, each counted per tray or per hand-carried stack:
| Step | Manual carry | Dolly delivery |
|---|---|---|
| Take trays off the truck | Lift each stack down | Roll the column off |
| Move to the receiving door | Carry, repeat trips | One roll per dolly |
| Move to the bread aisle | Carry, repeat trips | One roll per dolly |
| Place product or trays at the shelf | Lift each tray | Lift each tray |
| Collect empties | Carry stacks back | Nest empties on a dolly, one roll |
| Load empties on the truck | Lift each stack up | Roll the dolly on |
The shelf step is the same in both columns: every tray still has to be handled at the display. The savings are in the walking trips and in the lifts at the truck end. That also tells you where dollies help least: stops where the shelf is a few steps from the door, and very small drops where setting up and retrieving the dolly takes longer than one or two carries.
Measuring the savings on your routes
Use a simple time study rather than a general benchmark.
- Pick matched stops. Choose stores of each type you serve (large grocery, small format, convenience) with similar drop sizes.
- Time the stop, not the step. Start the clock when the truck door opens and stop it when the truck door closes, so retrieval of empty dollies is included.
- Run both methods. Time several visits manual and several with dollies, with the same driver where possible, because differences in driver pace can hide the equipment effect.
- Record drop size. Trays delivered and empties collected on each visit.
- Calculate per-stop savings by store type. Average the difference and note its spread.
Then convert to labor cost with your own numbers. For example, imagine a store type where the study shows 4 minutes saved per stop, on a 15-stop route: 4 x 15 = 60 minutes per route day. Multiply by route days and by the fully loaded labor rate you use for planning. The example input is illustrative; the method is the point.
Stack height: the reach limit comes first
A taller column means fewer dolly trips, but the top tray has to be lifted off by hand. The NIOSH Applications Manual for the Revised NIOSH Lifting Equation sets the upper limit of vertical reach for lifting at 70 inches (175 cm): “If V is greater than 70 inches, then, VM=0,” so the equation gives a recommended weight limit of zero for a lift that starts with the hands above that height. That does not set a legal limit; it means the equation offers no support for such a lift, which then needs a different assessment by your safety lead or a lower stack.
For a quick check, add the dolly height to the stacked tray heights. Using SPF Plastic Group’s published dimensions (SPF 2226 dolly, 5.8 in overall height; SPF 650 tray, 6.1 in overall height) and treating each tray as adding its full overall height, which overstates the stack because stacked trays seat into each other:
| Trays on the dolly | Top of stack, upper estimate |
|---|---|
| 9 | 60.7 in |
| 10 | 66.8 in |
| 11 | 72.9 in |
| 12 | 79.0 in |
On this upper estimate, ten trays keep the top rim under 70 inches and eleven do not. Because the real stack is lower than the estimate and the hands grip below the rim, measure an actual loaded column of your tray on your dolly before setting the limit; use the published stack height or stacking increment if your supplier gives one. A rule written as “no lifts starting above 70 inches” survives tray changes better than a fixed tray count.
How tray weight and lift frequency affect the same driver over a full shift is covered in our guide to tray weight and cumulative fatigue.
Doors, aisles and receiving: the feasibility check
A dolly that cannot reach the bread aisle saves nothing. Survey each store once and record:
- Door clear width. On accessible routes the ADA Standards require door openings to provide “a clear width of 32 inches (815 mm) minimum” (2010 ADA Standards, chapter 4). Compare the actual opening, measured with the door open, against the dolly’s width plus room for hands. A 22.6-inch-wide dolly such as the SPF 2226 fits a 32-inch opening; a 26.6 x 29.6 inch dolly such as the SPF 2629 should go narrow side first.
- Aisle and corridor width. Accessible walking surfaces are 36 inches minimum under the same chapter; stockrooms and back corridors may be narrower and are worth measuring.
- Ramps and thresholds. Slope, length and the height of each threshold; these set push force, covered in our guide to tray weight and dolly load limits.
- Overhead clearance. Lowest door header or obstruction on the path, against the stack height you plan.
- Where the dolly waits. Whether there is floor space at the aisle for a loaded dolly while the driver works the shelf.
Stores that fail one item stay on manual delivery for that item’s reason, and the route plan should say so.
Two operating models, two retrieval costs
The time study must match how dollies circulate, because retrieval is part of the stop.
- Return model. The dolly comes back on the same truck after the trays are worked. Retrieval cost is the roll back to the truck.
- Exchange model. The dolly stays with product (for example as a display base) and the driver collects the dolly left on the previous visit. Retrieval cost is low per stop, but the fleet must cover dollies sitting in stores, and losses rise if stores keep them.
Which model fits which route, and whether racks are the better tool for large stops, is covered in our guide to metal racks versus dollies.
What changes for the driver
Dollies replace the carrying trips and the truck-end lifts with pushing and steering. That shifts the physical load rather than removing it: pushing forces rise with gross weight, slopes and floor resistance, and the NIOSH lifting equation does not cover pushing, so the two need separate checks. Keep caster maintenance on the schedule, because a stiff caster raises push force on every stop.
A short decision rule
Equip a store type with dollies when the time study shows savings after retrieval, the store passes the door, aisle and ramp survey, and the planned stack keeps every lift start at or below 70 inches; otherwise keep it manual and record which condition failed.