themselves, while somewhat better received than the CoT (Generation 5) cars were at the time, have received some blow-back. Denny Hamlin was most critical, saying, "I don't want to be the pessimist, but it did not race as good as our generation 5 or regular CoT cars did." Hamlin received a $25,000 fine for his comments, which he refused to pay (NASCAR instead took that amount from his race winnings instead). NASCAR later faced criticism over the Generation 6 cars over the change to high downforce and reduced horsepower in later years that increased passing difficulty. Engine noise levels In 2007, a New York Times article cited two studies conducted by the National Institute for Occupational Safety and Health (NIOSH), conducted during races at Bristol Motor Speedway in 2005, which found that engine noise levels can reach as high as 140 decibels, which can do severe damage to a person's sense of hearing. One NIOSH engineer stated that 43 cars during a race was "equivalent to a jet engine". The first study focused exclusively on Bristol Motor Speedway, while the second study took other NASCAR race tracks into account, and both studies found that noise levels regularly exceeded 140 decibels when the race cars were accelerating at full throttle, and that the noise levels lasted, on average, about three to four hours, the average duration of a NASCAR race. The article cites seven-time NASCAR Cup Series champion Richard Petty, as well as other drivers such as Jeff Burton, now requiring the use of hearing aids due to hearing loss caused by engine noise. According to the article, a NIOSH engineer suggested putting mufflers on the cars in order to reduce the noise, but a NASCAR spokesperson stated that they already tried that in the 1960s, and it did not work as intended. Mufflers were re-tested with NASCAR's Next Gen car in 2023 and ran them at the Busch Clash that year. However, there remain challenges with the heat mufflers generated that are yet to be solved. Business structure and decision-making policies Since its founding in 1947 by William France Sr., the overall NASCAR organization has been majority owned by the France family, ensuring that the family controls a majority of the revenue that the sport generates. NASCAR is also criticized for its reluctance to promote some aspects of safety that it would have to pay for (e.g., traveling safety crew),