General Brazilian
trânsito congestionado / engarrafamento
Most common in everyday usage
São Paulo
engarrafamento / trânsito pesado
Often shortened to 'engarraf' in informal speech
Rio de Janeiro
trânsito congestionado / congestionamento
Commonly used in traffic reports
Portugal
trânsito congestionado / trânsito intenso
Portuguese tends to use 'intenso' more frequently than Brazilian Portuguese