Steven R Cox, Ting Huang, Wei-Rong Chen, Manwa L Ng
An acoustic study of Cantonese alaryngeal speech in different speaking conditions
The Journal of the Acoustical Society of America
measure impact automated photo speed enforcement school zones motorist speed speeding violation rates school travel automated enforcement cameras active school commuting hours installed around four elementary schools seattle washington usa 2012 examined effect automated enforcement motorist speeds speed violation rates citation period 10 december 2012 15 january 2015 compared warning period 1 november 9 december 2012 evaluated outcomes interrupted time series approach using multilevel mixed linear regression motorist speed violation rates decreased nearly half citation period compared warning period standardised incident rate ratio 053 95 ci 042 066 hourly maximum violation speed mean hourly speeds decreased 21 mph 95 ci 288 139 11 mph 95 ci 164 060 respectively impact automated enforcement sustained second year implementation automated photo enforcement speed limit school zones effective reducing motorist speed violations also achieved significant reduction mean motorist speed