David Shields, 34, crashed into Yvonne Blackman’s car which was queuing in a line of traffic on the A75 in Dumfries in February 2017.
The 66-year-old missionary worker never recovered and died weeks later in hospital.
Today outside the High Court in Glasgow Yvonne’s husband of 38 years Ralph Blackman, 78, urged drivers never to use their mobile phones while driving.
Mr Blackman, from Lockerbie, an HGV driver for 40 years, said: “I hope this sentence deters any drivers from doing the same. They should realise the suffering and hurt it causes to the victim’s family.
“I’ve was a professional driver for 40 years and I’ve never used my mobile phone. If I’m driving I just let it ring. I know the dangers and other drivers should know the dangers. Only a second’s inattention can be dangerous and he had 18 seconds with his eyes off the road.”
Mrs Blackman, a mother-of-four, had 18 grand children and two great grand children.
Her husband said: “She was very bubbly and fun-loving. She had a long life to live.”
Jailing Shields, from Drognan, Ayrshire, judge Lady Stacey told him: “I have seen a video of the crash and know you were paying heed to your mobile phone for 18 seconds. It was a very dangerous thing to do.
I know you did not intent the catastrophic result, but you should have known the terrible risk you were taking.”
Shields, who served as a lance corporal in the Royal Highland Fusiliers in Iraq and Afghanistan, wept as he was led away to the cells.
His defence counsel John Scullion QC earlier said: “He has asked me to apologised to Mrs Blackman’s family and is ashamed of his actions that day.
Damning footage from Shield’s truck showed him focusing on his phone for a full 18 seconds in the lead-up to the fatal smash.
Shields – who had a previous conviction for speeding – admitted causing death by dangerous driving.
Yvonne was on her way to meet friends to carry out missionary work when tragedy struck.
The mum-of-four was caught in heavy traffic on the A75 Gretna to Stranraer road around 8.30am on February 8 2017.
Shields, who was driving a truck for 911 Rescue Recovery from Stoke to Kilmarnock, and ploughed into the back of Yvonne’s Toyota Yaris.
Prosecutor Liam Ewing said: “Witnesses noted that the lorry did not appear to brake until a short distance before the collision, at which time it skidded or snaked.”
Yvonne’s car hit a BMW in front before spinning to a halt.
She died in hospital on February 23 from chest and spinal injuries caused in the crash.
Shields told police he only noticed “at the last second” that the “traffic was not moving,” and added: “I slammed the brakes on, slid and collided.”
But, analysis of the seven cameras in his truck’s cab showed his “attention had been on a dash-mounted mobile telephone”.
Mr Ewing said: “An analysis established he had been focusing on the phone...therefore failing to maintain proper observations of the road ahead.
“(This was) for a period of 18 seconds prior to reacting to the presence of the car.”
He is seen driving while checking the phone before his cab shudders as it hits Yvonne’s car.
It is not known what he was doing on the mobile at the time.
Part of the charge Shields pled guilty to stated he did “repeatedly interact with and focus your attention” on a phone.
He was banned from driving for seven years and six months.