SAO PAULO – The Formula One season ends Sunday at the Brazilian Grand Prix with drivers raving about the rule changes that were aimed at encouraging passing and improving racing.

Although Sebastian Vettel dominated the season and won the title with four races to spare, there was plenty of excitement on the track with a significant increase in passing in nearly all races.

A study by Mercedes showed there have been more than 800 overtaking maneuvers in the first 18 races, reaching “record levels” in F1.

Nearly half of those passes came thanks to the new drag reduction system (DRS) implemented this year, which allows drivers to adjust their rear wings to increase speed and facilitate passing.

“It is to me very obvious that we have improved big time,” Mercedes driver and seven-time world champion Michael Schumacher said Thursday. “We’ve had incredible races this year. It doesn’t always work out perfect, there is some room for improvement, but in general it has contributed a lot for some great racing.”

The excitement on the track also came as a result of the return of the hybrid KERS power-boost system and the new Pirelli tires, which produced more pit stops and more late drama as drivers had to manage wear more aggressively.

“If you watch every race this year there have been some amazing overtaking maneuvers,” 2009 world champion Jenson Button said. “Most races had you on the edge of your seat. It’s very unusual to have that. This season we’ve had so many special races. They’ve done a good job with the regulations.”

Even tracks that used to produce dull races saw an increase in passing and excitement, with drivers switching positions and battling wheel-to-wheel more often than previous years.

The study showed total overtakes reached nearly 1,500 when considering all circumstances in which cars were passed, including at the start, because of damage or involving the three slowest teams.

“I think people are enjoying it,” said McLaren driver Lewis Hamilton, Button’s teammate and the 2008 F1 champion. “I really have enjoyed it.”

Mercedes said the data from its study was calculated using a combination of video, timing data and GPS technology.

The study showed Schumacher was one of the top overtakers with 111 passes, behind only Toro Rosso driver Sebastien Buemi (112).

The race in Turkey produced the most passes with 85, followed by Canada (79) and China (67). The fewest passes came on the tight streets of Monaco (16), Australia (17) and India (18). The average of clean passes reached 45 per race, 25 normal and 20 with the DRS enabled.

Drivers say the DRS has been the main reason for the increase because the drag reduction system gives a trailing driver a significant advantage.

The adjustable rear wing is set by the push of a button from inside the cockpit, lowering a flap and increasing straight-line speed. The technology is made available every time drivers get within one second of the car ahead.

Many drivers and teams were skeptical of the DRS when it was announced, saying passing would become too artificial, and some still think it has made overtaking too easy. FIA has said the system was a success, although it admits some minor changes loom.

“Obviously there have been races where you think it’s too easy to overtake, there is always going to be negatives to something like that,” Button said. “But the positives outweigh the negatives. I think we’ve had some great racing this season on circuits where we never had overtaking before, especially with two competitive cars. You can have a bit more of a fight now.”

The rear wing cannot be used over the first two laps for safety reasons, but KERS, which debuted in 2009 but was temporarily abandoned last year, was available throughout this season. The system stores kinetic energy generated in breaking, allowing drivers to transform that energy into more power for a few seconds at the push of a button.

Pirelli replaced Bridgestone as the series’ sole tire provider and introduced compounds that brought in-race strategy back to F1. It deliberately designed tires that degraded more quickly, prompting an increase in pit stops and in the number of strategy options.

“Pirelli has done a good job to help (racing),” Williams driver Rubens Barrichello said. “Together with the DRS and the KERS, I think the show has improved. Let’s hope that’s the way Formula One is going to be for the long term.”