"I wanted it to be like a mobile space to raise awareness ... I chose the Breast Cancer Foundation New Zealand because it's a charity that does a huge amount to support men and women in the fight against breast cancer."
William's Aunty Helen, who lives in the UK, is currently fighting stage four of the disease.
"Because of living here in New Zealand, Mum, Dad and I haven't been able to help with her fundraising as much as we would have liked, so I asked Mum and Dad if I could fundraise over here instead and they said yes straight away."
William has also set up a Take Action fundraising page on the Breast Cancer Foundation New Zealand website where people can donate money. William says he is grateful for the support of his family and friends and has already nearly raised his goal of $500.
"My girlfriend's mum said at the beginning of the season that she would donate $10 for every race I win. I think she's had to donate about $70 so far. I think there is about $400 raised altogether so far and my family over in the UK have donated too."
Matthew has been involved with speedway all his life.
"Mum was pregnant with me while she crewed for dad when he raced in the United Kingdom.
"Even up to the day before I was born she was helping change his wheels and refuel the car. My first meeting was when I was two weeks old."
William started driving ministocks when he was 12 and 2018 is his final year in the class.
"I like speedway because it's not only about racing or winning, but also about being able to meet up with friends who race, all over the country."
William has been getting a bit of flak for his overalls which have a pink strip down the side, but when he explains why, the hassling stops.
"Some try and rip into me a bit because my car is pink and also because I have pink on my overalls. One guy said that I needed to give my girlfriend back her overalls, but it's okay.
"He looked a bit silly when he realised why I had them.
"A few boys at school have taken the mickey about my car and overalls — I just laugh it off. The ones who go to speedway or know me well and why I'm doing it thinks it's really cool though."
William's friend Rebecca Barr drives a superstock car and is also raising money for the same charity. The pair decorated a truck carrying their cars and entered the Hawera A&P parade recently — winning second place. They split the $300 prize money to put into their own fundraising accounts.
William's parents Richard and Helen Hart say they are proud of their son.
"There can't be too many 16-year-old boys who would choose to paint their car bright pink and wear pink striped overalls and have pink ribbons flying off the wing, but he has and that shows what kind of kid he is really. He's not a follower, he likes to be a little different, not to stand out as such, but to have his own identity and that makes us very proud parents."
Helen says they have had a lot of support and thanked the Stratford Speedway for being so supportive of William's fundraising mission.
William travelled to Rotorua last weekend to compete in the New Zealand youth ministock championship Ministocks in Paradise where he was placed third overall.
More than 100 drivers competed for the Tubby Norris Memorial Trophy during the event which is the biggest youth ministock event in New Zealand. William qualified as the top points scorer in his group on Friday night before going on to be placed third overall.
