[GreenYes] Split Body Collection Vehicles

["Peter Anderson" <anderson@recycleworlds.org>]

    With regard to the email traffic concerning split body collection of
recyclables and refuse on the same truck.

    Certainly, there can be a potential benefit from dual-collecting both
streams on the same vehicle in the sense that the second separate collection
for recyclables is thought to be eliminated.

    However, it is important to note that this benefit is very often
overstated, and indeed, in many cases, dual collection would actually
increase costs.  For the following reasons, among others, it is important
that anyone considering this option conduct a detailed local-specific
analysis of their particular circumstances before plunging ahead on what
could be a very poor economic decision for their situation:

    (1) COMMON TRANSFER STATION/MRF. Dual-collecting trash and recyclables
can only really function effectively where the waste stream goes to a
transfer station at the same location as the MRF.  If the vehicle has to go
to two different locations to off-load, any benefits are rapidly dissipated.

    (2)  RECYCLE SETOUT RATE. Look at the set-out rate for recyclables.  A
typical setout rate of 50%, for example, means that the second separate
recycle fleet only actually stops at half of the stops on the routes, and
passes by without stopping at the other homes. In this regard, remember that
the time the collection vehicle spends on the route primarily can be broken
down between the time-at and the time-between stops. The time-at is not the
major place where savings arise with dual collection: rather it is the
time-between that can be saved, that along with the time spent off the route
(to and from the garage, to and from off-loading, on breaks, and any
dead-heading).  This is because, once the truck stops, the operator has to
bring the various trash cans and recycle bins from the curb to be loaded if
there is a setout.  The time-between stops along with the times off the
route, however, is run just once instead of twice when a separate fleet is
used.  A typical breakout between the two might be 5 seconds between stops
and 20 seconds at the stop.  Thus, in the typical situation, only
approximately one-quarter of the time on the route is saved, and all of the
time off the route.  In a typical 9 hour day, with three hours off the route
(one to and from garage, one off loading and one on breaks), and one and a
half hours for the one-quarter of the time on route representing the time-at
the stops, the best time savings if everyone set out recyclables from dual
collection is half the time (3 hours off route + 1-1/2 hours on route =
4-1/2 hrs saved, which is one half of the nine hour day.  As the setout rate
declines toward 50% from100%, however, this breakdown shifts to only 42% of
the total hours that is saved.

    (3) ROUTE DENSITY. Look at the density of the routes as the second major
determinant of whether the hoped-for benefits of eliminating the second
fleet will be realized.  Because it is the time-between, not primarily the
time-at, this means that the less dense the route (and hence the greater the
time-between stops), the greater the savings from eliminating the second
fleet of trucks and the more dense the route, the less savings to be
garnered.

    (4) TRUCK UTILIZATION.  Although I have high hopes for more innovation
in the future (and have proposed several ideas to manufacturers), almost all
split body trucks today have the ratio of that split fixed at the
manufacturer.  This has major implications. It means that if the incoming
loads on a given day's route do not match the ratios built in at the
factory, one compartment will top-out before the other, requiring the
vehicle to leave the route to off-load  when the other compartment is not
full.  If, for example, the unfilled compartment of a truck split 50%/50% is
only 60% full when the first tops out, then the overall truck utilization of
its internal volume is only 80%.  A rated 30 yard vehicle actually produces
only 24 effective yards.  This means the vehicle may have to off-load twice
instead of once a day, subtracting a second hour to go off-route to tip,
which wastes 100-150 stops from which to collect.  Careful measurements of
the standard deviation of the recycle and waste streams volume around the
average each day is absolutely essential to get a bead on this problem.

    (5) SECOND FLEET LESS EXPENSIVE.  Also remember that, depending upon how
automated your recycle collection is, the cost of the recycle fleet in terms
of capital charges can be substantially less expensive than the
hydraulic-heavy packer trucks.


    BOTTOM LINE:  Dual collecting recyclables and solid waste on the same
truck is usually grossly oversold.  Be careful and do your own analysis
before plunging ahead.


Peter

______________________________
Peter Anderson
RECYCLEWORLDS CONSULTING Corp
4513 Vernon Blvd. Suite 15
Madison, WI 53705
Ph:    (608) 231-1100
Fax:   (608) 233-0011
Cell:   (608) 345-0381
email: anderson@recycleworlds.org
web:  www.recycleworlds.org

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