MEMRAMCOOK, N.B. -- A Nova Scotia Mountie who worked to educate the public about the need to slow down when driving past emergency vehicles was killed after being struck while helping motorists change a flat tire.

Const. Frank Deschenes, a 12-year RCMP veteran stationed in Amherst, died when a utility van collided with his police car and an SUV shortly after 6 p.m. Tuesday on the Trans-Canada Highway near Memramcook, N.B.

Deschenes had stopped to assist two people in the SUV change a tire, RCMP Cpl. Jullie Rogers-Marsh said Wednesday.

"It is extremely challenging to describe what it feels like when we lose one of our own," said Asst. Commissioner Brian Brennan.

The officer, a 35-year-old former member of the force's famed Musical Ride who got married this summer, died at the scene. The two people in the SUV were treated for their injuries.

Police say the van's driver was taken into custody after being released from hospital. No charges had been laid as of early Wednesday evening.

Rogers-Marsh couldn't say why the Nova Scotia officer was in New Brunswick at the time, but did confirm that Deschenes was on-duty and in uniform.

Cpl. Darren Galley, who had been Deschenes' supervisor in traffic services in Amherst, said they were involved in initiatives to inform the public about legislation that requires drivers to slow down and move over when emergency vehicles are stopped along the highway.

"I think traffic was his passion," Galley said from Moncton, where he now serves. "He came to work everyday and did a 100 per cent job ... He was always friendly, always a happy, go-lucky guy and he's going to be sadly missed."

Galley said the officer had transferred from Bible Hill, N.S., to Ottawa at one point to become part of the Musical Ride before transferring back to Nova Scotia at the Amherst detachment.

Deschenes was also a tactical unit member and had won the Queen's Diamond Jubilee Medal.

Nine years ago, Deschenes was praised for preventing a possible train derailment with just seconds to spare by putting himself in the path of an oncoming train.

Early on Dec. 1, 2008, a car was stuck on railway tracks just south of Brookfield, N.S., after striking a pole and spinning out of control as a CN freight train approached.

Deschenes acted calmly and coolly by crashing his police cruiser into the car, pushing it out of the way just 45 seconds before the train arrived. The RCMP said at the time the officer's selfless actions saved lives by preventing a derailment.

Brennan said the fact that Deschenes had stopped to help change a flat tire spoke to the kind of person he was.

Ralph Goodale, the public safety minister, issued a statement offering condolences to Deschenes' family, friends, and colleagues.

"The death of a police officer is a stark reminder of the sacrifices and bravery of our police women and men who put themselves in harm's way each and every day to keep Canadians safe and secure," Goodale said.

Brennan said he couldn't provide many details about Tuesday's accident since it is under investigation.

Rogers-Marsh said investigators would have to determine if everyone was in their vehicles at the time of the crash or standing by the vehicles.

Rogers-Marsh said it has been a difficult time for members of the force.

"When our members deal with fatal accidents it's never easy to deal with that. It's certainly very difficult when it's one of your own co-workers or somebody that you might know. Our thoughts go out to the member's family, friends and his co-workers," she said.

The eastbound lanes of the highway were closed for several hours while emergency crews attended the scene. The highway was re-opened Wednesday morning.

With files from Alison Auld in Halifax.