"My waters broke around 6am this morning. We thought we had heaps of time to get organised and had been expecting a longer labour and birth because Dillon's had taken 25 hours. But this morning the first contraction was at 6.45am and the baby was born at 8am."
Husband Jacob Scott-Simmonds, 34, described it as a "pretty manic" day.
After Miranda experienced her first couple of contractions, he "basically went shotgun approach" and threw some bags together to take her to the hospital.
"The next battle was to get Miranda down the stairs and into the car. By the time we were backing out of the garage she was saying she wanted to push and I was telling her not to," Jacob said.
"You really couldn't print what her response was to that bit of advice. It wasn't friendly."
He "pretty much just had to reverse out into the [rush hour] traffic", getting abuse from frustrated drivers, he said.
"We got to the KFC roundabout and it was obvious we weren't really going to make it. So I called Gillian [the midwife] again and we had her on speakerphone in the car. I think my comment to her was, 'this s*** just got real'."
Gillian told them to pull over, while she called for an ambulance to meet them at the Z service station.
"It felt like an age for the ambulance to get there, but in reality was only a few minutes," Jacob said.
"By this stage Miranda was crowning so the ambos arrived in the nick of time. We rolled her out of the car onto 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 paramedics as being "absolutely awesome".
"I was able to cut the cord as well."
The couple, who run the Nyne clothing label in Mt Maunganui, have been together 14 years, and married for four. They have a 2-year-old daughter called Dillon, but have yet to decide on a name for the latest addition to the family.
"We haven't named our new daughter yet, but she's already been nicknamed 'Z'," Jacob said.
"A couple of my friends have asked me whether we got free pies at the service station."
The couple also wanted to thank their midwives, the paramedics who helped deliver little 'Z', and the hospital staff.
"Everyone's been great," Jacob said.
However, the couple were said to be overwhelmed by the attention the birth received.
"We have been amazed by all the interest to be honest, we didn't think it was anything too out of the ordinary," Miranda said.
"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."
