The 39-year-old has bought a majority stake in Team Green, for whom he has been racing in Cart this year. The outfit will now be called Andretti Green Racing.

Andretti will continue as one of the team's drivers - and he said that he wants Scot Dario Franchitti and Canadian Paul Tracy to stay on as the other drivers.

It is anticipated that ex-Cart champion Andretti will enter the team in the rival Indy Racing League next season as his greatest ambition is to win the Indianapolis 500.

But Andretti said he has not yet decided which series to run in - and some US insiders believe that the American could run the team in both championships.

Former team boss Barry Green is to step back into a consultancy role.

Andretti said that a decision about which category the team would race in would be taken after consultation with sponsors.

Andretti, son of former Formula One world champion Mario Andretti, said: "No decision has been made as to where we will be racing.

"We just wanted to get this put down and we will work on the sponsorship side of it to see which way we go."

Andretti won the Cart title in 1991 and has won more races in the category than any other driver in its history.