First generation body (Generation 5) 's
Aaron's, Inc. Toyota after his notorious qualifying crash in
2008. McDowell would walk away from the incident relatively unscathed. Criticisms of the CoT began with its first tests, with the magazine
Speedway Illustrated noting the car's poor performance in traffic (February 2006 issue). The
Winston-Salem Journal also noted extensive criticism of the project during 2006 testing, with drivers becoming more vocal by July 2007 and most fans rejecting the model, citing the falsity of many of its technical claims; one angle of criticism was the differing philosophies of NASCAR officials Gary Nelson and John Darby, with Darby a particularly ardent supporter of the CoT based on a misreading of the sport's competition packages.
Jeff Gordon and
Matt Kenseth were pointedly critical of the car's poor performance in traffic, with Gordon stating after the
2007 New England 300, "I'd like to know who it was who said this car would reduce the
aero push because I could have told you from when I first drove this car that it would be worse."
Kyle Busch, who won the very first race with the car at Bristol in 2007, proclaimed that the car "sucks" afterward and expanded on this criticism at Dover in 2008 in noting how the CoT was "hitting a wall of air" in the wake of a leading car, thus neutralizing ability to close up on leaders. On April 4, 2008, while in a qualifying run for the
2008 Samsung 500 at
Texas Motor Speedway,
Michael McDowell's right-front sway bar broke, causing him to lose control of his car and strike the wall outside of Turn 1 head-on at 185 MPH. McDowell's car subsequently barrel-rolled eight times as fire came from the engine compartment and came to a stop at the exit of Turn 2. McDowell emerged from the Toyota unharmed. The car, along with the
SAFER barrier on the track wall, was praised for its safety, as the speed upon impact of the crash was about 30 miles an hour more than
Dale Earnhardt's fatal accident. It has been claimed that the bulky rear wing that was affixed to the rear of the car from 2007 to early 2010 increased the severity of many on-track incidents by causing cars to flip over or go airborne at high speeds. • On the final lap of the
2009 Aaron's 499 at Talladega, leader
Carl Edwards attempted to block
Brad Keselowski in order to prevent Keselowski from passing; when Keselowski didn't give, Edwards was turned into the air and Edwards's car bounced off of the hood of
Ryan Newman's car and flipped into the catch fence, then came to a rest in the middle of the track further down. Edwards was uninjured, but the crash was compared to an accident at Talladega in 1987 where
Bobby Allison went airborne and hit the
catch fence in a similar location. Allison's crash (coming at speeds 20 MPH faster than Edwards' crash) ripped out a 100-foot section of the catch fence, while Edwards' crash only bent the support poles. Seven spectators were injured in Edwards' accident from debris. The aftermath of the accident spawned questions about the aerodynamic features of the CoT, the nature of
pack racing with
restrictor plates, and the safety features of Talladega Superspeedway. Video replay showed that despite deploying, the car's
roof flaps did nothing to stop the car from flipping – a common failing of the devices dating to their very first month in use – and the second hit from Newman flipped the car higher. • In the
2009 AMP Energy 500 – the fall race at Talladega, Ryan Newman was spun backwards at high speed in a late race crash, and then flipped backwards (landing upside down on
Kevin Harvick's hood) and ended up on his roof.
Mark Martin also barrel rolled in a crash during the same race, but instead of lifting in the air like Newman, his car was hit from behind, causing the weight of the car to shift to one side and pull the car onto its roof, rolling once. • At the
2010 Kobalt Tools 500 at Atlanta – the second to last race to use the rear wing – Carl Edwards made deliberate contact with Brad Keselowski (in retaliation for several events including the Talladega race the prior season), causing Keselowski to turn backwards and once more flip over despite the roof flaps being deployed. Keselowski flipped over once and crashed on his side door. Edwards was parked for the rest of the race and put on three-race probation. These three accidents – as well as the general consensus that the wing made the car look like a sports car rather than a stock car In spite of strong criticisms of the CoT's handling characteristics and the racing styles it created, it also produced one of the most competitive periods of time in NASCAR history. the first four CoT races in 2007 produced more "quality passes" (a pass of a top-15 car under green-flag conditions) than their 2006 counterparts. From 2007 to 2012, 28 different drivers scored a victory (in 196 races), including several first-time winners.
Second generation body (Generation 6) For 2013, NASCAR allowed manufacturers to design a brand-new body style for the COT chassis that resembled a given production car even more. The changes were largely cosmetic, with hopes of returning mechanical grip to drivers. At the 2012
Ford Championship Weekend the body of the car made it the Gen 6 car by
NASCAR. During the 2012 season, it was announced that Ford would use the Mk.V
Ford Mondeo, known as the Fusion in the Americas,
Toyota would continue to use the 2013
Camry, while the
Holden VF Commodore, rebadged in North America as the Chevrolet Super Sport (SS), replaced the
Chevrolet Impala and
Dodge announced they would use the
Charger. However, soon after, Dodge announced their withdrawal from the sport, after being unable to convince other teams to switch to Dodge to replace
Penske Racing (which returned to Ford). Key among the changes for the car included a carbon fibre hood and decklid, shaving 160 pounds from Cup cars, and new improved safety bars added to the roll cage. The roof flaps were increased in size to prevent the airborne accidents that marked the CoT's early life. 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. The Generation 6 car was succeeded by the
Next Gen car in 2022.
NASCAR Xfinity Series The Nationwide Series (now Xfinity Series) debuted its own version of the CoT in July 2010 at
Daytona International Speedway, running four races that season before fully implementing the car in 2011. The Xfinity car used the same chassis as the Cup Series, but featured an extended wheelbase of . The second-tier series also utilizes different body style, primarily marketing American
pony cars such as the
Ford Mustang.
NASCAR K&N Pro Series/ARCA Menards Series In 2015,
NASCAR's regional series, the then-
K&N Pro Series East and
West along with the
ARCA Racing Series (which NASCAR purchased in 2018, followed with rebranding of the East and West Series under the ARCA banner in 2020), the final series to still use the Generation 4 style body, introduced a new body style based on the Generation 6 Cup Series cars. Unlike the Generation 6 cars, the K&N Pro Series/ARCA car continues to use a front valence instead of a splitter. Again, three bodies are available—the Camry, Commodore/SS, and Fusion; these cars continue to use be based on their 2013-spec body styles even with changes to their Cup Series counterparts. In 2022, a Ford Mustang bodystyle (based on the 2021 Generation 6 body) also became available. ==Models==