This new "Generation 6" racecar debuted at the 2013 Daytona 500 and its supporting races. The testing and design of the car began in May 2010 and involved an unusual level of cooperation between the manufacturers (Chevrolet, Ford, and Toyota) involved. The 500 and subsequent race at Phoenix Raceway, however, caused controversy, as passing was limited and drivers such as Brad Keselowski and Denny Hamlin were critical of the car's ability to pass; the controversy was exacerbated when NASCAR fined Hamlin $25,000 over his comments. The view was also expressed that the car's slow development time and lack of available parts made drivers reluctant to take chances, with improvement expected with more time invested into the car.