(4) “The formation of ordinances for the prevention of this carelessness. If the department has the effective cooperation of the police department and of the magistrates, in the enforcement of the ordinances, then and only then can this particular condition be reduced to a practical minimum. In an attempt to enforce ordinances forbidding the throwing of litter in the streets, New York City in 1915 caused the arrest of 5,400 persons for violating ordinances relating to street conditions of the scattering of refuse. In addition to these arrests in the last three months of the year more than 18,000 formal written warnings were issued for the violation of ordinances.” Street Cleaning Factors and Standards The conditions and factors controlling the amount and frequency of cleaning of any pavement, are as follows: 1. Density of horse drawn vehicles and other traffic. 2. Width of street. 3. Character of district and population. 4. Location of streets. 5. Proximity of streets and alleys. 6. Location of public buildings, parks, etc. 7. Kinds and condition of pavement. A study made by the Chicago Civil Service Commission definitely established that the density of horse traffic, which is the total number of horses passing through a given street divided by the width of the street, is the principal factor which determines the number and frequency of cleanings one street should be given. The Commission has also learned that there are at least thirty-eight distinct movements which a street cleaner makes in street cleaning work. Of these some have been found to be unproductive, resulting in loss of time and energy and less effective street cleaning. The most important of these, according to the Commission’s report, are as follows: Observation of time wheeling push carts into alleys or other dumping places, disclosing that practically one-fifth of time was consumed in this activity. The study disclosed that some sweepers are more efficient than others, due to the stroke of the broom which they make. The practise of hitting a broom on the pavement is not necessary on dry pavements and very seldom on wet pavements. Effective and practical street cleaning can be obtained by bringing the brush down forcibly at the beginning of each stroke, thus reducing the work at least 15 per cent. The time schedules disclosed that time lost by street cleaners in dodging horses and automobiles where traffic is dense is unappreciable and does not exceed 8 per cent. of the total time in the business district and not more than 2 per cent. of the total time in the outlying district. It is occasioned more through congestion of traffic than through density of traffic. In cleaning light traffic asphalt pavements it was disclosed that after the one morning thorough cleaning three- fourths of the area to be covered during the remainder of the day does not require thorough cleaning. The Commission believes that scoops