I tend to diagree, DrRox, because the roadblock should be first, before they head south for the detour and then west for the pitstop. Besides the fact that the roadblock is usually first, they seem to start in the central Rio area (where the airport, tram and roadblock are) and work away from it.
Perhaps I misunderstood your post but it seemed like you were suggesting that the detour was before the roadblock.