"By this stage Miranda was crowning so the ambos arrived in the nick of time. We rolled her out of the car on to the stretcher and five minutes later in the ambulance the baby arrived.
"I didn't have a clue what was going on to be honest. I was in the back of the ambulance thinking 'Holy, this was not the birth plan'."
He praised the "absolutely awesome" paramedics.
"I was able to cut the cord as well."
Mr Scott-Simmonds said the morning was "pretty manic" following the first contraction at 6.45am, "then another one pretty close after that so I was thinking, 'hang on, maybe I should be timing these and maybe we should start packing some stuff'. We had nothing packed".
He bundled Miranda into the car with a couple of bags of stuff for her and the baby and "after Miranda had stopped swearing" they rang their midwife.
"By the time we were backing out of the garage she was saying she wanted to push and I was telling her not to. You really couldn't print what her response was to that bit of advice. It wasn't friendly."
Taking on rush hour traffic, Mr Scott-Simmonds said he had told their midwife "this s*** just got real" before she had advised them to pull over and call an ambulance.
The family were transported to Tauranga Hospital where midwife Gillian was waiting and Miranda and their new baby girl were checked over.
"We can't thank Gillian, Kelly, the ambos, and the hospital staff enough, everyone's been great," Mr Scott-Simmonds said.
"We haven't named our new daughter yet but she's already been nicknamed 'Z'. A couple of my friends have asked me whether we got free pies at the service station."
Mrs Scott-Simmonds said their second daughter was due on February 8 "but her sister arrived three days early as well".
"We have been amazed by all the interest to be honest, we didn't think it was anything too out of the ordinary. We have a friend whose wife gave birth in a car a week ago. But I guess doing it in front of thousands of people going to work was a bit different."
St John territory manager Ross Clarke said the Mount Maunganui St John crew were excited to be called to the job and deliver the baby safely on the forecourt.
"It's nice to see this end of the spectrum instead of the other end which is what we usually get called out to."
Z Energy Hewletts Rd site manager Vicky Barnett said it was an exciting morning at the station.
"I haven't had a baby born at our site before," she laughed.
She was waiting outside the ambulance to find out what had happened when the midwife arrived and alerted her to the birth inside the ambulance.
"It's still quite exciting," she said.
She gave birth where?
*A Thames mother gave birth in the back of a car in July 2014 as she was driven across farmland to avoid a fallen tree and powerlines blocking the road to the hospital.
*Diana Thomson's seventh baby was born halfway between her car and an ambulance stretcher at Kaikohe's Z Station in July 2014. The couple were forced to stop when she went into labour while they were driving from their home to the Bay of Islands Hospital in Kawakawa.
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