Since 1959 police officers have had the authority to settle traffic violations by immediately collecting fines from the violators. However, it is uncertain how officers decide which cases to settle through fines and how much the use of such fines varies. To answer this question, the statistics of five departments with high fine levels and of five departments with low fine levels are analyzed, and interviews are conducted with officials of seven departments whose fine levels in 1975 were considerably higher or lower than in 1973. The statistics derive from quarterly reports of police fines recorded by district prosecutors' offices in 1973 (and in certain cases, in 1975). Results indicate that the number of department fines depends on the local traffic situation. About three-fourths of all fines are for parking violations. The numbers of immediate fines and of official reports instead of fines vary from officer to officer. Differences are due to some extent to divergent levels of departments' activity in detecting parking violations. But the actual extent to which the fine system is used by the police and public cannot be determined exactly because of the dearth or accurate statistics. However, interviews with officials suggest that a fairly large number of 'necessary' official citations results from citizens' unwillingness to go the police station to pay the fine at once. As the number of areas for imposing police fines and the amount of fines are both to be increased in the immediate future, police methods for reporting fines and official citations should be improved, relating both figures to specific officers and to particular offenses. The number of official reports for violations must be included in the prosecutors' quarterly reports. Accurate statistics could perhaps be gathered by replacing the present system with statistics published by the Central Office of Statistics at intervals of 1 month, 1 quarter, 1 year, and several years. Tables and several notes are supplied.