Hot cars, hot girls, hot music and glowering, independent teens were the key ingredients of the sub-genre of 'Hot Rod' films that emerged during the 1950s. By the middle of the decade, they were being made at a rate of one a week and played to drive-in audiences. The films were made on low budgets and featured unknown actors, as it was the car, not the plot or the characters, that was the film's centrepiece. The genre continued to develop well into the 1960s and 1970s and spawned cult classics such as Easy Rider and Two Lane Blacktop.