F1 could adopt a "league table" for Grand Prix venues to ensure only the best events are on the calendar, says Ross Brawn.

The sport's schedule is back up to a record 21 races for 2018 and the expectation is that F1's owners, Liberty Media, will move the number up towards 25 in forthcoming years.

F1 2018: Race calendar, launch and test dates

Brawn, F1's managing director of motorsport, believes the sport can cope with further expansion but should not purely be focusing on quantity - and would ideally like to see a system where the poorest-performing events are dropped and replaced.

"The crucial thing is the quality of the race. There's no value in just putting the number of races up," Brawn told British Airways' Business Life magazine.

"But if we can provide great races in great locations throughout the world, then we should consider it.

"I'd love to see in the future a league table of races, where over time we've got a waiting list of top-class circuits and promoters that are waiting to get into Formula 1, and then if there's any race that is not working well, you relegate that and put a strong race in."

Two of the sport's most historic races, France and Germany, return to the calendar this year, although no new additions have yet been confirmed for 2019 onwards.

F1's bosses plan to roll out more street demonstration along the lines of last year's London Live at cities around the world this year, with commercial chief Sean Bratches recently telling the German press that Marseille, Berlin, Milan, Shanghai and Miami are all on the agenda.

Speaking to reporters last week, McLaren chief Zak Brown said the planned Miami event could eventually be followed by a race in the southern Florida city.

"I'd be surprised if we can get it done for next year just because of the infrastructure which would need to be built up," the American said.

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"But l think it's definitely a precursor to another race in North America and they are definitely very active in conversations around Miami. It's definitely warming up America and that market."

Plans are already afoot for a street race on the streets of Copenhagen in Denmark, with F1 chief Chase Carey visiting the city last month to discuss proposals with local dignitaries.

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