OR Practice—Making a Clean Sweep: Simulating the Effects of Illegally Parked Cars on New York City's Mechanical Street-Cleaning Efforts

On a peak day, New York City's Department of Sanitation deploys 354 mechanical sweepers to pick up a substantial portion of the 100 tons of litter deposited daily on the city's 6,000 street miles. Field studies conducted by the department indicated that the major obstacle to doing a thorough job of cleaning was the number of illegally parked cars blocking the curb. We used Monte Carlo simulations to determine the increase in sweeping effectiveness that could be expected from significant reduction in illegally parked cars. The simulations provided information that was critical to the decision making process and resulted in the redeployment of 30% of the city's mobile traffic enforcement agents. The redeployment led to fewer illegally parked cars and more curb space available for cleaning.