Officials worked overnight to add grooves to the straight and most drivers approved the changes after a 15-minute practice session early Sunday to test the new surface at the 2.6-mile (4.2-kilometer) Anhembi temporary street circuit.

“It worked well, it's not a problem anymore,” Brazilian rookie Ana Beatriz said. “There is enough grip there now.” Drivers complained Saturday after they were not able to fully accelerate without losing control at the straight.

They said it was like driving on ice.

It was extremely dusty where the grooves were added, but drivers clearly had a lot more grip and lap times were significantly lower.

Cars were sliding and slipping throughout the straight on Saturday and several drivers crashed there in practice.

The straight goes through a stadium-like Sambadrome that stretches for about a third of a mile (500 meters) and is the only part of the track with concrete instead of asphalt. It is where Sunday's 75-lap race is scheduled to start and finish.

The surface is usually painted for the traditional Carnival parades at the Sambadrome, but it remained slippery even though organizers removed the paint ahead of the race.

The street circuit is one of the highlights of the season, with the Sambadrome and the series' longest ever straight, which is just short of a mile (1.6 kilometers).

Organizers had to set up the track in only about three months following the announcement that the IndyCar Series would be coming to Brazil for the first time since the CART series raced in the Latin American country from 1996 to 2000.