Officer Jordan Jones says you don't get a lot of time to get CPR going, and he knew every second counts.
VIDEO: Firefighter unknowingly responds to help dad after heart attack
The woman's husband, Jeff Costello, said he was in a panic as his wife's face turned purple.
Together, they pulled her to the side of the road and quickly started CPR.
After three sets, she began to breathe on her own. Tina Costello was then rushed to the hospital.
Doctors say Tina had a heart attack so severe only 10 percent of people survive it.
Fortunately, it appears she will make a full recovery because of the quick actions of Officer Jones.
"That's the first time, like, I fully saved somebody's life," Jones said.
It was a miracle that Jones happened to see the speeding truck.
Tina's husband said they were still 20 minutes away from the hospital.