I find that I get energized on my short (20 minute) drive home. Maybe it's the change in context, but even if I'm mentally fried at 5 I find that I can at least get another hour or two.
I used to have a less than 5min commute and it was perfect for "resetting" my mind. I now have about an hour commute; most nights it doesn't matter how much energy I had when I walked out of the office, by the time I get in the house I barely have enough energy to put something in the microwave and eat before passing out.
That happens to me, I have a 20 minute commute too. I do it by motorcycle and it makes me wake up in the morning and be ready to do whatever I want to do in the afternoons.
I find motorcycles amazing for this. Even a ten minute ride completely energizes me. It might have something to do with the total focus required.