"Lesson learnt," he said, adding he was more used to manual transmissions, and thought he was stopped.
"A moment's inattention, it was a silly mistake.
"I don't normally drive an automatic car. I thought I was bloody stopped."
When pointed out that drivers should not handle their phone while driving, Mr Mark said this was a reminder.
"Yeah, you know and you know and you know ... I'm heading to this meeting, I knew I was running fine to the line.
"But none of us are above it."
He said the pickup driver was "laughing" and his towbar wasn't damaged, but an observer wasn't so amused.
"This old boy, he was standing on the side - he had a few things to say - very, very righteous."
The same "righteous old boy" called the Times-Age later that morning, but did not want to give his name.
"I was standing on the footpath, the truck had stopped," he said.
"I thought [of Ron Mark's car], he's not going to stop."
The man, visiting from Waikato for a wedding, said the speed was slow but was unimpressed with a mayor "driving around on a phone".
He thought Mr Mark was talking on his phone, but Mr Mark said definitely not.
Carterton District Council voted Mr Mark a second-hand council vehicle in December. He had been using his own vehicle during his first term as mayor.