 Mike Gallagher. I'm Sergeant Dotz with the Albemarle County Police Department's Traffic Unit. What do you know about perception response time? Essentially, it's your reaction time. It's how long it takes for a deer, ball, dog, or pedestrian to enter your view while driving and you hit the brakes. Now imagine driving 35 miles an hour on a street designed for 25 miles an hour. Your stopping distance is much farther than the street was designed for, creating unsafe conditions for you and others utilizing our roadways.