4 KudoZ points awarded for this answer. Comment: "Before I posted my question on Kudoz I had already considered both "laggard" and "lingerer", but they hadn't satisfied me much - I was hoping for another option. I found an interview by Mika Hakkinen - and a story on what he said made by a newspaper - complaining about backmarkers. Plus, it's the word that's most associated with speed-driving in general (F1, motor-racing etc.). I believe it's the best word to be used. But thanks a lot everyone else. Your participation is *always* important."