Andy Musliner was sitting on the floor playing cars with his then-3-year-old son when it occurred to him that the cars needed roads.

"It's an obvious pairing — toy cars go with toy roads," Musliner said. "If you have a toy car, it needs a road to drive on, yet the toy industry had not created an opportunity for kids to make roads."

That idea led the Baltimore area resident on a quest to start a toy company and ultimately create a new category — tape as toy.

Musliner started InRoad Toys, which makes PlayTape, rolls of tape printed to resemble roads fit for tiny vehicles. The tape sticks to walls, floors, tables or any flat surface, and pulls up without damaging surfaces.

It appears to have filled a need, meeting demand from parents who want to encourage creativity and from retailers looking for something new in the toy category. It's also a twist on the consumer tape industry's growing decorative and crafting segment.

When PlayTape was introduced three years ago, it was sold at a few small toy stores. Now it's sold in 35 countries. Wal-Mart sells it at 3,500 stores and online. It's also available online at Toys 'R' Us, select Target stores and O'Reilly's Auto Parts.

"Vehicle play is an evergreen category that kids have naturally gravitated toward for generations," said Joe Contrino, a spokesman for Toys 'R' Us. PlayTape "takes a simple, but unique spin on the category."

InRoad projects sales this year of between $2.5 million and $5 million.

"PlayTape is the world's simplest toy," and therein lies its appeal, said Musliner, InRoad's CEO. "Kids who play with toy cars can make a road anywhere they want. Parents are really interested in enabling their kids to use their imaginations and enabling them to develop their motor skills, to really play and get off the screens."

"My kids love it," said Christy Barbaran, a Baltimore mother of boys 5 years and 21 months old. "We went on a road trip in March, and that saved us a few times. They created elaborate tracks over wood floors in the hotel and entertained themselves. They run their Hot Wheels over it for hours and hours."