Studies and experiments have been carried out to examine the risk compensation theory. In one experiment subjects were asked to drive go-karts around a track under various conditions. It was found that subjects who started driving belted did not drive any slower when subsequently unbelted, but those who started driving unbelted did drive consistently faster when subsequently belted. A study of habitual non-seat belt wearers driving in freeway conditions found evidence that they had adapted to seat belt use by adopting higher driving speeds and closer following distances. In another study, taxi drivers who were habitual non-wearers were timed over a route with passengers who did, and others who did not, insist on the driver wearing a belt. They completed the route faster when belted.