In a series of field trials of co-collection vehicles that store separated recyclables in bins located directly behind the cab, improved design was shown to increase productivity over manual trash collection by as much as 29 percent (see chart).
The field trials were conducted between September and November 1993 by two private haulers and one municipality. These included Truk-Away, Providence R.I.; Best Trash, Denver; and the city of Loveland, Colo. Additional data was provided by Jerry Kreider of R.G. Smith, Des Plaines, Ill., who monitored and timed a demonstration vehicle used by several Chicago area haulers.
Co-collection technology combines traditional manual trash collection with recycling collection technology. The driver collects the recyclables while another employee, on the back of the truck, collects the trash. Bagged recyclables can be placed in with trash or separated and stored in another part of the co-collection vehicle.
For the purpose of the field trials, a right-hand stand-up cab was used to co-collect the recyclables along with trash. The results showed that co-collection serviced the same number of homes as traditional manual trash collection. A two-man, rear-load design with a conventional cab and relatively low recycling rates serviced 450 homes. In comparison, the right-hand stand-up cab increased the number of stops to 580 homes, a 29 percent increase in productivity. This was accomplished in spite of a smaller packer - 18 vs. 20 cubic yards - and a higher recycling rate, with set-outs of 66 percent vs. approximately 20 percent.
According to the study, the right-hand stand-up drive enabled the vehicle operator to collect the recyclables in little more than the time the vehicle must stop to pick up the trash at any given home.
In the time trials conducted in the Chicago area, a traditional two-man rear load trash crew, with a driver in the cab and an employee collecting trash, spent 34 seconds per stop collecting trash only. When the driver switched to right-hand stand-up drive and began collecting separated recyclables in bins, the time per stop increased to 38 seconds. Over the course of a full day on route - 400 recycling stops on a route with almost 600 trash stops this approach added 27 minutes to the day.
Another trial which combined side loaders for both recyclables and trash collected from fewer stops but increased the efficiency by reducing the number of man hours per ton of trash, from 1.05 to .71.
Variable rates enhanced the results in Loveland. Its bag-based rates have achieved a 62 percent reduction in landfilled waste, enabling a two-man crew to co-collect the trash and recyclables from 1,100 homes daily. Loveland's co-collection system has met or exceeded the efficiency of the automated system they were also considering.