Men push a car stucking in the mud on a motorway in Nimba County, Liberia, 28 July 2019. Most highway roads in the rural parts of the country are unpaved. The government of President George Weah has promised to build roads to connect all big cites of Liberia. (Photo by Ahmed Jallanzo/EPA/EFE)

Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

Bronze medalist Carlos Coloma Nicolas of Spain celebrates after finishing third in the cross-country cycling mountain bike race at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Saturday, August 20, 2016. (Photo by Patrick Semansky/AP Photo)

People on motor bikes celebrate American President Barack Obama's visit to Kenya by holding up a photo, center top, of the president and First Lady Michelle Obama in Kisumu, Kenya, Saturday, July 25, 2015. President Barack Obama heralded Africa as a continent “on the move” Saturday as he opened a U.S.-sponsored business summit in Kenya, the East African nation where he has deep family ties. (Photo by AP Photo)

Ricardo Azevedo rides his Honda NX 200 motorbike, which he converted to be powered by water, in Salto, northwest of Sao Paulo, Brazil, August 6, 2015. The Sao Paulo civil servant built the motorbike, which can cover up to 500 kilometres (311 miles) fuelled by just one litre of water. Dubbed “Moto Power H2O” the bike is powered by the process of electrolysis, which breaks the water molecule down into its constituent elements. (Photo by Nacho Doce/Reuters)

Traveling Chairso n Hakone Road. (Photo by Kusakabe Kimbei)

An extreme Vespa enthusiast rides his bike after attending weekend festival for extreme Vespas in Semarang, Central Java, Indonesia, July 22, 2018. Every year, Indonesians from teens and granddads, to mechanics and students, gather in eastern Java to celebrate their love of the iconic Italian Vespa scooter. (Photo by Darren Whiteside/Reuters)

In this March 30, 2019 photo, Andrea Dovizioso of Italy falls from his bike during a Moto GP free practice run at the circuit in Termas de Rio Hondo, Argentina. Despite the fall Dovizioso raced in the third pole position on Sunday and finished in third place. (Photo by Nicolas Aguilera/AP Photo)