Department of Transportation and Mobility Initiates 'Operation Splash' Published on June 07, 2023 In an effort to protect the public on city streets during Tucson's summer thunderstorm season, the Department of Transportation and Mobility (DTM) is initiating "Operation Splash." Beginning Wednesday, June 14, DTM staff will be on call 24 hours a day, seven days a week, through mid-September. Tagged as: , TDOT, News