The Department of Public Works runs street sweepers to keep streets clean and items out of the storm drains that should not be there. However, to provide full leaf collection city-wide would require more specialized equipment that is very expensive to not only purchase, but to maintain. Those machines suck up everything and have been known to pull in small animals as well. Much of the detritius under the leaves can damage the machine. Most cities that have decided to use this method of leaf collection now regret it.