The Billower Bike is used for in-land transportation. It is a wide bike with three wheels (two big ones in the rear, and a smaller one in front) and its engines are powered by his Moku Moku no Mi powers. Additionally, Smoker can traverse water with the bike.
Some time ago, the Billower Bike was designed and built to work with Smoker's abilities. It is unknown if he built it himself or if someone else made it for him.
Smoker first used the Billower Bike to chase down Monkey D. Luffy in Loguetown and then again to contact Hina outside of Arabasta. It is unknown what happened to bike afterwards as this was the only time he was seen using it.
This is the first vehicle seen in the series that requires a Devil Fruitpower to work, although it was not shown, but instead confirmed in an SBS.
↑SBSOne Piece Manga — Vol. 27, Oda confirms that Smoker's bike can travel over water.