A baby born on the A66 in freezing conditions is recovering well from the experience, medics said.
Sienna Waring was delivered by her father Andrew as he tried to get her mother Daniella to hospital in terrible driving conditions.
She was born near Stockton-on-Tees moments before paramedics arrived at the scene.
Sienna, the couple's third child, weighed 10lb 1oz and was taken to Darlington Memorial Hospital for a warm-up, but was said to be doing well.
Her father had opened the passenger-side door and knelt outside the car helping his wife as she gave birth.
Mr Waring, from Catterick, North Yorkshire, said: "The weather was very bad and I struggled to find somewhere to pull over and barely had time to ring 999 when the baby started coming.
"Having been present at the birth of our two other children, I just copied what I had seen then.
"I opened the passenger door and knelt in the snow to deliver the baby."
The Great North Air Ambulance Service (GNAAS) land-based crew were first at the scene, followed by a regular crew from the North East Ambulance Service.
Philip O'Donnell from GNAAS said: "The conditions were challenging to say the least and we initially had difficulty finding the family.
"But after driving up and down the road a couple of times we were able to locate them and inform the ambulance service as to their whereabouts.
"The baby had arrived shortly before we arrived so the hard work had been done, but we were able to check baby and mum over before the ambulance crew arrived and took her on to hospital.
"It was a lovely job to be involved in and we'd like to congratulate them on the new arrival.
Student paramedic Claire Roberts said: "I was concerned about them being on the side of the road in the freezing cold, but was very excited as it was my first potential delivery.
"When we arrived, the GNAAS crew were already there keeping Sienna warm so it was a case of making sure they were ok, cutting the cord and getting them on board the vehicle and away to hospital as soon as possible.
"It was a really lovely experience and it's great that mum and baby are doing well."
Labour Ward sister, Anne Hodgson, said: "Daniella and Sienna had been in freezing temperatures so our priority was making sure they had skin-to-skin contact to warm Sienna up.
"She's being cared for in a special cot which has a mattress filled with warm water so we can regulate her temperature.
"She has been regularly monitored throughout the day.
"We have no cause for concern and they're both doing really well despite their experience."