PHOENIX - Aggressive driving and road rage can escalate in an instant.
It could start with the finger, maybe to graduate to ramming, then in extreme cases, to murder.
An incident in 2016 left 19-year-old international student Yue Jiang dead. On Friday, Holly Davis was sentenced to 25 years behind bars for her senseless death.
The gun violence watchdog group Trace, named Phoenix as one of the worst places for road rage involving guns. The latest data shows 18 regional cases of road rage involving a gun between 2014 and the beginning of 2017.
"We're one of the fastest growing areas in the country. We continue to add drivers to our roadways from other states," said Trooper Kameron Lee, with the Department of Public Safety. "We've added one million in the past 10 years."
Trooper Lee said aggressive driving, which often leads to road rage, is why they have troopers in stealth cars out with one primary purpose.
"We take it very seriously, and that's why we put unmarked vehicles out on the roadway to try and curb behavior before it escalates to a road rage incident," Lee said.
According to the National Highway Traffic Safety Administration, 37 percent of aggressive driving incidents involve a firearm. Trooper Lee said if you find yourself the moving target of road rage driver, first check your own emotions.
"Put your pride aside. Back away and then call us with a description of a vehicle that is driving that way," Lee said. "Don't engage, don't make eye contact, don't antagonize in any way."
And whatever you do, don't stop and get out.
"Vehicles will pull up to a stop light, and then drivers get out. Never do that. You don't know who you're confronting. That person could have just committed a serious crime," Lee said.