The judge also set aside the transport minister’s 2008 decision to declare sections of the N1 and N2 as toll roads.
This means that if Sanral wants to go ahead with tolling, it will have to start the entire process from scratch.
City of Cape Town mayor Patricia de Lille described the verdict as “a victory for all South Africans”.
She said the City of Cape Town had gone out of its way to provide the court with all the evidence it needed.