She said it may be "interesting" with some of the youngsters, given their sensory issues, but she says many boys with autism have a fascination with big trucks.
"It's a passion for them, so it's a great match," she said.
The money will help Autism NZ Wanganui branch projects and advocacy work, such as supporting parents accessing Government departments or assisting families at school meetings.
She said the branch also has a successful session for children with autism at the Boys' and Girls' Gym Club in Wanganui.
"It's really for all special needs children, and their friends and family. It's going very well."
However, swim lessons at the Splash Centre have been a bit more difficult to fund and organise, given a term of lessons costs about $120 per child.
"We would really like to be able to support parents there. It's very good for autistic children because the water is so calming."
The event has been organised by the Wanganui branch of the Road Transport Association, BP has come to the party, supplying $3000 in cash and $500 in fuel vouchers for the big trucks' big day.