Forza Horizon focuses specifically on casual street racing, rather than professionally on race tracks, as it takes place on a map of temporarily closed public roads. The open-world map that players can explore is based on the U.S. state of Colorado. It features multiple types of races, such as circuit races, off-road rally, and traditional point-to-point races. The roads feature both AI traffic and, when playing online, other player-controlled drivers.[5] Players may challenge the other racers they encounter to a one-on-one race to a given location. The races start at the current location, and finish at a randomly generated way-point, usually more than 500 metres away from the player and their opponent. A skill system is implemented in the game; players earn popularity during races by driving aggressively. Acts such as drifting, jumping over obstacles and getting a car on two wheels all contribute to the player's popularity level. These can be chained together in a combo, which in turn affects the money players are paid at the end of a given race.[6] As a player's popularity level increases new special events are unlocked, such as races against helicopters and planes.[6]
In an interview with Turn 10's creative director Dan Greenawalt, he stated the game was developed in close relation to real music festivals—namely Coachella—and that he envisioned a more relaxed game-play experience than other games in the Forza series, while keeping a more realistic handling style. Being the main theme of the game, a large focus of the game is on the festival itself and activities surrounding it, rather than just racing.[7]