Brazilians Walter Salles and Daniela Thomas have an agreement to co-direct films every few years which take a close look at life in Brazil.

They have two films to their joint credit - Foreign Land in 1996 and Midnight in 1998 (as well as the Loin Du 16eme short from the Paris, Je T'Aime portmanteau in 2006).

Their latest, Linha De Passe, which screened in Competition at Cannes, looks at four brothers all trying to reinvent themselves in different ways in the chaotic city of Sao Paulo. Their mother is played by Sandra Corveloni, who picked up the best actress prize.

'It's a city of 22 million people, with 300,000 motorcycle couriers and at least 200km of traffic jams every day,' says Salles.

'What we wanted to do was look at the possibilities of these four brothers living in the outskirts of the city trying to break through social barriers but colliding with the violence that is a reality in Brazilian society. It's about young kids trying to rebaptise themselves in a way through areas like soccer or religion.'

There is also a racial angle in that the youngest son is half-black with the only clue to his father's identity being that he is a bus driver - a character inspired by a teenage Sao Paulo joyrider who stole buses.

But Salles says the film is no City Of God for Sao Paulo, instead filled with the 'humour and wit that is characteristic of today's youth. City Of God served its purpose for its time. But the family in this film doesn't live in a slum and you don't see drug-dealing or a single gunshot.'

Thomas developed the screenplay for four years with George Moura and Braulio Mantovani while Salles worked on other pictures, and assembled the four actors, including Vinicius De Oliveira, the now-grown child actor from Salles' 1998 Central Station. 'We wanted to work with a new generation of Brazilian talent,' says Salles, 'in front of and behind the camera.'

'We were looking to shoot what we found in the real-life streets,' Salles continues. 'While we were shooting, the actors lived in the house where their characters lived. The neighbours in the film are the real neighbours, the church-goers are the real church-goers, the soccer players are the real soccer players.'

And, as in Central Station and Foreign Land, the children in the film live without a father. 'The absence of the father is one of the characteristics of Brazilian society,' says Salles. 'There may be a historical reason for that in that our founding fathers from Portugal came to Brazil, took all the silver and gold and then left. In the US, the founding fathers stayed.'

Salles, who is preparing a film of Jack Kerouac's seminal beat novel On The Road, has finished principal photography on a companion piece documentary in which he follows the trip taken by Kerouac's alter-ego Sal Paradise through North America.

'We met several people who are still alive that he met in On The Road and interviewed remaining beat poets like Gary Snyder, Lawrence Ferlinghetti and Diane di Prima and spoke to people who were directly influenced by Kerouac like David Byrne and Wim Wenders.'

Going by the working title Searching For On The Road, Salles says it will be completed before he begins production on the feature which he co-wrote with Jose Rivera and which is being backed by Pathe: 'I am hoping to start shooting in the fall, or maybe spring 2009.'