NASCAR has added two more tests for Sprint Cup teams to run their new-for-2013 cars in December and January.
The Cup cars will be overhauled for next season, with a new set of rules enabling manufacturers to give their cars a more distinctive look.
Series organisers have already put together a test programme for the new cars, and they announced this week that two extra sessions will take place at Charlotte Motor Speedway on December 11-12 and January 17-18.
NASCAR vice president of competition Robin Pemberton said: "We've put together an aggressive and extensive testing schedule for the new car and we are pleased with how things are progressing.
"We have the opportunity to provide teams with a couple more optional test dates at a mile-and-a-half race track as we look to provide the most competitive racing we can.
"The new car has generated a lot of excitement and anticipation and we're looking forward to seeing it in competition next year."
The January test will be the second chance for teams to hit the track at the start of 2013, as it comes a week after Daytona Preseason Thunder on January 10-12.