When police were searching Interstate 93 yesterday morning for a reported armed man, they called in the N.H. State Police airplane to help.
The single-engine plane already was up, patrolling the state’s major highways for speeders, distracted, aggressive or impaired drivers.
It’s in the air most days, according to Lt. Kevin Duffy, commander of the state police Special Enforcement Unit.
While he wouldn’t be specific, he said the plane covers the whole state, concentrating on Interstates 89, 93 and 95, and Route 101.
That unit has six troopers, the plane and a civilian pilot. This isn’t some new surveillance technique. Duffy said state police have had aircraft since the mid- to late 1970s.
When bad weather grounds the plane, those troopers are on the ground, using Doppler or laser radar on enforcement patrols.
On Wednesday morning, police arrested Felix Rivas Torres, 21, of Manchester for reckless driving on Route 101 in Raymond. He was clocked traveling at 111 mph by the aircraft detail.
While the plane was up for several hours that day, police said, they stopped 45 drivers, and issued 24 tickets and 21 warnings. Seven of the drivers stopped were traveling at 85 mph or higher.
“What the aircraft does for us is give us the ability to track higher speeders, who wouldn’t be interdicted by troopers on the side of the road, running radar,” Duffy said. “When you’re traveling 111 mph, it’s kind of an eye-popping observation.”
Police use highway markings, visible from the air, to calculate how fast a motorist traveling 1,500 to 2,000 feet below is traveling. There are five “zones” in each stretch of marked highway, one after another and each 1,500 feet in length, Duffy said.
“As a car enters a zone, the trooper in the air essentially starts a stopwatch on the vehicle,” he said. “They use a calculation based on how fast you make it through the zone to determine how fast you’re going.”