Reaction Times of Police In New Study
Senta Scarborough
The Arizona Republic
June 28, 2003

TEMPE - A defense consultant on the second-degree murder case against former Chandler police Officer Dan Lovelace is conducting groundbreaking research on officer reaction time in deadly force encounters.

 For the past three weeks, Bill Lewinski, a law enforcement professor at Minnesota State University, has tested 101 officers' trigger pull responses using a 9 mm Glock handgun and a computer to learn how the Tempe officers perceive and react when faced with a threat.

The trigger, wired to a computer, is tracked every 10 milliseconds to record officers' reaction to a colored-light stimulus. Five experiments duplicate varying degrees of visual distractions.

"For the first time, we are applying the science of movement, reaction and perception to shooting situations," Lewinski said. "We want to understand better what happens between the onset of a stimulus to shoot and the final round fired by an officer."

Lewinski is using some of the same science to evaluate the actions of Lovelace in the shooting death of Dawn Rae Nelson on Oct. 11.

Nelson was shot by Lovelace when she attempted to flee from a drive-through at a Chandler pharmacy.

"I am taking a solid look at how the principles of reaction that I have been researching apply in that shooting," said Lewinski, who is working at the request of Craig Mehrens, Lovelace's attorney.