Curbside collection of recyclable material: Simulation of collection activities and estimation of vehicle and labor needs

This paper presents a mathematical model that can be used to estimate the time required to collect recyclable material (route time) by simulating the activities of a collection vehicle driving over its route. Data obtained by observing the collection of recyclable material in The Village, OK, were used to determine parameters for the model. The validity and robustness of the model were tested by comparing model-predicted route time to observed route time. The model was able to predict route time within 8%. Simulation procedures are presented that can be used to estimate route time under conditions not actually observed-for instance, very low or high rates of material being set out for collection. The simulation procedures, incorporating randomly assigned set-out distributions, indicate that set-out distribution (proximity of houses setting out materials) has little effect on route time. Vehicle and labor needs for the curbside collection of recyclable material in a hypothetical town are estimated to demonstrate a practical application of the simulation procedure. The results indicate that if set-out rate were to increase from 20% to 30%, labor needs would increase by 34% and an additional vehicle would be needed to serve the same number of households. Increasing set-out rate from 20% to 40% would result in a labor requirement increase of 68%. Calculations such as these are particularly significant if a program to increase participation is being considered.