The traffic division at the Chattanooga Police Department is responsible for figuring out what and sometimes who causes the city's worst crashes.

They are also responsible for keeping our streets safe. 

The 11 member team's efforts were recently recognized by the Tennessee Highway Patrol in helping the district lead the state in reducing fatal crashes in 2016. 

Enforcement is only part of the job for CPD's traffic investigators like Master Patrol Officer Joe Warren. The team also investigates the city's worst crashes. 

"They're very complex in nature. There's a lot of moving pieces to the puzzle that you have to put back together and to do that successfully, we have to be able to document the scene," Warren said. 

Physical evidence like tire marks, debris, and measurements are pieces of that puzzle investigators like Warren consider when figuring out how a crash happened. 

Technology known as total stations and a 3-D scanning system helps put the evidence in motion.

"It just really recreates the scene for us so we can study it later and present it to the courtroom and present it to the families and show them what happened," he added. 

Tools that help the traffic team too by identifying issues with roadways so a fix can be found.

Warren says it's all part of the job, one he wants drivers to know is meant to keep them safe. 

The 3-D scanning system is also used in the major crimes unit when investigators recreate crime scenes.