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Traffic Safety Bureau

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The mission of the Traffic Safety Bureau is to provide the safe movement of traffic throughout the City of Costa Mesa. Officers investigate traffic collisions, enforce traffic laws, and assist patrol officers. The bureau also has a Major Accident Investigation Team, which responds to critical injury and/or fatal traffic collisions.

The Traffic Bureau is commanded by a lieutenant and consists of two sergeants, 13 officers, one traffic investigator, nine part-time police aides, and two volunteers.

The Traffic Safety Bureau utilizes grants from the California Office of Traffic Safety (OTS) to conduct Driving Under the Influence checkpoints and participate in awareness campaigns about distracted driving, motorcycle safety, and pedestrian and bicycle safety. For more information on OTS, please visit their website at

The Traffic Safety Bureau coordinates traffic control for special events in the City, including the OC Fair, OC Marathon, and the Chargers Training Camp, as well as police transports. 


(714) 754-5675

The Traffic Safety Bureau is led by Lt. Clint Dieball, who is a Costa Mesa native and a 23-year veteran of CMPD. Dieball began his law enforcement career initially with the Orange County Sheriff’s Department as a deputy sheriff for three years. In 1996, he joined the CMPD as a police officer and held assignments in Patrol Services, the South Coast Plaza Detail, and Detective Bureau in property and crimes against persons. In 2006, Dieball promoted to corporal and became a field training officer, before promoting to sergeant in 2008. As a sergeant, he worked Patrol Services and later became the Field Ops Administrative Sergeant. In 2018, he became the Community Policing Unit (CPU) Sergeant. Throughout 2019, Dieball oversaw the department’s temporary bridge-shelter and homelessness efforts with CPU throughout the City and in both Fairview and Talbert Parks, which led to him being recognized as the Police Supervisor of the Year for 2019.

Dieball was raised in Costa Mesa and attended Sonora Elementary, Davis Intermediate, and Costa Mesa High School. He also attended Orange Coast College before transferring to the University of Southern California where he graduated with a Bachelor of Science in Public Policy and Management. He later obtained a Master’s degree in Public Administration with a minor in Public Finance from National University in Costa Mesa.