Dirt Wurx USA - the premier SX/MX track design and construction company in the world � is the exclusive supercross race track design and construction firm for Live Nation and the Monster Energy AMA Supercross Series. With more than 18 years of global experience in the field, Dirt Wurx USA�s highly talented crew of designers and heavy equipment specialists not only build the world�s most visible tracks, but are also accessible for affordable track design and construction at the local level