Their father, Grant Roberts, died in a 2012 crash caused by a visitor who had been in New Zealand for one day.
Ms Pipson, of Geraldine, said after the death Sean had asked her: "Why can't we make sure they [tourist drivers] are safe?"
That led to the petition and yesterday's visit to Parliament.
Building concern over tourists' driving has led to vigilante action including the taking of keys and an assault.
There was none of that anger from Ms Pipson or her sons - they praised moves such as a code of best practice adopted by rental car companies, but, politely, suggested more should be done.
"We would like to see along with that ... some kind of competency test," Ms Pipson said.
"Not a long one, just some sort of competency test that they understand [road] signs and rules."
"I understand that it's not going to be a driving test," Sean added.
"But even if it was a 10-minute [simulator] or movie that showed the [road] signs."
Earlier in the meeting, Kevin Bowler, chief executive of Tourism New Zealand, said greater training and materials for overseas travel agents could influence tourists to stop and think, "is self-drive for me?".
When the meeting was over, Ms Pipson told a friend how nervous she had been, while her eldest child handled media questions.
Taking action
• Sean and Cody Roberts, 10 and 9, addressed a select committee at Parliament yesterday on their petition.
• The brothers helped gather more than 31,000 signatures on a petition calling for tourists to be required to sit a practical test before driving in New Zealand.
• In 2012, their father Grant Roberts was killed in a crash caused by a tourist who had been in the country for one day.