Fueled by his design skills and his son’s love of school buses, a Kansas City man has conceived what could become the first school bus Lego set.

Nathan Roberts said he was surprised to discover recently that there has never been an official school bus Lego set. Being a fan of the classic plastic building bricks — and having a 4-year-old son who is fascinated by yellow buses — Roberts decided to design his own set. Roberts said that his 4-year-old son enjoys seeing yellow buses lined up at school when they pick up his older brother. “I think he particularly loves school buses because the color is so iconic and inviting,” Roberts said.

Inspired by his son’s bus zeal, the Lego enthusiast spent about five months off and on designing his school bus set, which uses a total of 572 pieces. The 10-passenger bus has a removable roof, a stop arm and a crossing arm that swing out, a hood that opens to reveal the engine, and even a fire extinguisher on board.

Roberts used a computer model to create images of the set concept, although he also assembled a physical brick version.  “It was important for me to actually build it,” he said, “because it’s hard to know what really works and looks good with only a digital version.”

After his “Classic School Bus” concept was fully fleshed out, Roberts submitted it to Lego Ideas, which lets fans pitch their ideas for new Lego sets. Proposals that attract at least 10,000 supporters qualify for review by a Lego board of designers and marketers. Those that are chosen by the board go into production and are sold around the world, according to the company’s website.