Observations suggest that the flow speeds in extragalactic radio jets are relativistic on parsec scales. This evidence includes rapid variability, brightness temperatures in excess of the inverse Compton limit and even the motion of individual features with apparent superluminal velocities. In contrast, FR–1 flow speeds appear to be non–relativistic on kiloparsec scales (the case is not clear for FR–2 sources); consequently, the possibility of jet deceleration has been explored.