Shaffer, Paul F.

English

Research Papers in Economics

SYSTEMS FOR HANDLING GROCERY PRODUCTS
FROM SUPPLIER TO DISTRIBUTION WAREHOUSE
by
Paul F. Shaffer
The Paul F. Shaffer Company
Miami, Florida
Background of Study
In the previous report of driver
and tractor-trailerdelays for grocery
deliveries (contract#E-13186-ARS-75)
studies were conducted at four ware-
houses, each having a different procedure
for scheduling grocery truck receipts as
follows:
a. All truck receipts are scheduled
as to arrival time.
b. Truck receipts were not scheduled.
c. Truck receipts were not scheduled
except priority was given to unitized
loads.
The report concluded that an ap-
pointment system where all appointments
are made for the time when the dock
opens will not reduce total waiting
time. A central check-in station for
drivers where all purchase orders are
well organized, with both “ti and hi”
and pallet size instructions,will reduce
driver waiting time. Factors other than
whether the trucks are scheduled or not
may be of equal significance to an ap-
pointment system. A warehouse with suf-
ficient doors to handle peak receiving
will reduce the delay for a door assign-
ment. The use of backhauls will give
dock personnel more flexibility in bal-
ancing the work load. A dock with an
adequate staging area and equipment to
clear the product from staging to
permanent storage eliminates congestion
at the receiving doors.
The total cost of waiting varied con-
siderably and was apparently not related
to an appointment system. This cost
varied from 83c to $2.62 per truck receiv-
ing.
The report recommended that the best
method of evaluating the effectiveness of
an appointment system would be a “before
and after” study, in one firm. One of
the cooperating firms was planning to con-
vert to the appointment system. Addi-
tional studies of grocery receiving were
made in this firm prior to the installa-
tion of the appointment system. when the
system was operating effectively, studies
were conducted for an equal number of
truck receiving. The results of the
“before and after” study are detailed in
this report.
Methodology
In the firm which was converting to
the appointment system, a minimum of 25
additional truck receiving were made
between 5:00 AM and noon on peak truck
receiving days; typically Monday through
Wednesday, before the appointment system
became effective. The following informa-
tion was recorded:
a. The arrival time of each inbound
trailer, in the firm’s gate.
February 77/page 94 Journal of Food Distribution Researchb. The time elapsed between arrival
and park at a grocery receiving door.
c. The time trailer unloading begins.
d. Any unusual waiting time.
After initiation of the truck
scheduling program, the information
specified in a- through d- was obtained
for a minimum of 75 truck arrivals, from
Monday through Wednesday. The same
labor rates and equipment costs were
used as in the previous study.
Discussion
A total of 94 truck arrivals were
recorded prior to initiation of the
appointment system and 84 truck arrivals
were recorded after the system was in-
stalled. During the observation of the
receiving and the analysis of the data,
it was determined that the waiting time
for supplier trucks and the firm’s back-
haul trucks were significantly different.
The backhaul trucks were parked at the
receiving door for up to three hours
before unloading. It was decided that
the waiting time for the two types of
receiving; supplier and backhaul trucks,
should be reported separately. This
separation had no effect on the evalua-
tion of the appointment system since the
total waiting time for the backhaul
trucks was almost identical in the before
and after studies. It was virtually
impossible to obtain an adjusted waiting
time for the backhaul trucks because the
observers could not determine whether
the waiting time was due to the lack of
equipment and personnel for unloading
or due to balancing the receiving work-
load.
As in the previous study; the four
firms actual and adjusted times were
reported
the same
report.
Journal of
for driver and tractor-trailer,
procedure was used in this
Where the observers determined
Food Distribution Research
that the delay was not relevant to the
study, it was underscored and omitted from
the comparison of the before and after
study. These delays and the reason for
them are detailed on the summary sheets.
Cost of Driver and Tractor-Trailer
Waiting Time
The installation of the appointment
system in Firm #3 reduced the actual wait-
ing time for supplier trucks by 8.47 minutes
(33%) and the adjusted waiting time by
6.17 minutes (31%), Table #1. There was
no significant difference in the waiting
time for the backhaul trucks.
The total cost of driver and tractor-
trailer waiting time for supplier trucks
was reduced from $3.14 to $2.17 per receiv-
ing, Table #2. This reduction of 97c per
truck receiving is considered to be
significant.
Conclusions
The appointment system in Firm #3 was
effective in reducing the waiting time
for drivers and equipment.
There was no significant change in
the management or operation of the truck
receiving dock after the installation of
the appointment system.
As was indicated in the previous
report, the availability of additional
receiving doors, the central driver check-
in, the rapid clearing of the receiving
area and the availability and completeness
of the purchase orders (including stacking
information) would further reduce waiting
time.
In firm #3, all backhauls are unitized
thereby effecting efficient unloading with
a fork lift. However, normal procedure
for all supplier trucks, whether palletized,
slip sheeted or handstacked, was to hand-
stack unload onto small pallets or relayer.
February 77/page 95This created dock tie up that could not
be corrected by an appointment system
as full loads took several hours to
unload.
Table #1 Driver and Tractor-TrailerWaiting Time inomklholesale Warehouse Before
and After Installation of an Appointment System (in minutes).
No Appointment System Appointment System
Arrival to Park-Begin Total Arrival to Park-Begin Total Reduction
Park/Door Unload Time Park/Door Unload Time Wait-time
Supplier Trucks*
Actual 15.12 10.71 25.83 9.03 8.33 17.36 8.47
Adjusted 13.98 6.16 20.14 8.22 5.72 13.94 6.20
Backhaul Trucks**
Actual 7.15 41.10 48.25 17.55 30.51 48.06 .19
* 55 receiving in both studies
** 39 receiving in before studY and 29 receiving in after study
Table #2 Total Cost of Driver and Tractor-TrailerWaiting Time Before and After
Installation of an Appointment System; Supplier Trucks Only
No Appointment System Appointment System
Total Waiting Time 20.14 min. 13.94 min.
Labor Cost of Waiting* $2,42 $1.67
Depreciation for
Tractor-Trailer* Lz2
Total Cost of Waiting $3.14 $2.17
* Based on $7.20 per hour
*>tFrom Table #2 of previous report; $2.16 per hour for tractor-trailer.
February 77/page 96
*********
Journal of Food Distribution Research

SYSTEMS FOR HANDLING GROCERY PRODUCTS FROM SUPPLIER TO DISTRIBUTION WAREHOUSE

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