With lawmen hot on her tail, a runaway German shepherd led authorities on a harrowing highway chase down Interstate 495 yesterday afternoon, tying up traffic before she was lured into a state police cruiser with the promise of a tasty fruit-and-nut granola bar.

When 7-year-old Lexi finally gave up on her four-legged getaway and agreed to be peacefully “taken into custody,” trooper Malachy Higgins said the huffing pooch leapt into the driver’s seat of his Ford Explorer, spilling his coffee and switching on the siren.

“I’m a dog owner myself, so I know how it would feel if my dog was lost,” Higgins told the Herald, admitting that when he spotted a cold and frightened Lexi darting in and out of traffic, he pictured his own 5-year-old Australian shepherd, Teddy, in the same predicament.

“I have a wife and a 1-year-old,” Higgins said. “I know how devastating it would be for them if we lost him.”

Along with trooper Dana Atkinson, Methuen police Sgt. Tom McMenamon and the driver of a Department of Transportation vehicle, Higgins said officers blocked off all three travel lanes about 1 p.m. as Lexi high-tailed it south into Lawrence.

When he realized Lexi wasn’t going to voluntarily get off at the next exit, Higgins said he managed to corral the wayward canine into the front seat of his cruiser by offering her his granola bar, which he keeps for when he’s in a tight spot.

Lexi never got to taste the healthy treat because Higgins was afraid she might be allergic to nuts.

“I just wanted to give her the impression that she was going to eat something to get her into the cruiser,” he said. “We actually gave her some dog food once we got off ?the highway.”

It wasn’t until Lawrence Animal Control officer Ellen Bistany brought Lexi back home to Alton Road in Methuen that her owner, Rose Marchand, realized her beloved pet had embarked on the wild adventure.

“She called and said, ‘I’m in the driveway and I got Lexi,’ and I said, ‘What do you mean you’ve got Lexi?’ ” Marchand told the Herald. “She said they found her sitting in the road, and I was thinking she meant out on (Route) 110 and she said, ‘Nope, 495,’ and I said, ‘Oh dear Lord in heaven. If she wanted to sit down she could have sat down anywhere, she had to wait until she got out onto the highway?’ ”

This isn’t the first time Lexi has made a break for it, Marchand said.

“We do everything we can, we have a fence up and everything but she still manages to find a spot to get out,” Marchand said, admitting she was mortified to learn that her dog had created such a fuss.

“When they said they were tied up with her for about half an hour, I said, ‘Oh Lord, I’m so embarrassed,’ ” Marchand said. “Usually when she goes out she goes right to the car because she loves to go for rides. This is the first time she’s ever left the yard and gone down the street.”

When asked if she had a message for the emergency responders who made sure Lexi made it back home safely, Marchand offered a heartfelt apology and said, “Thank you all so much and I am so sorry that this happened.”