I generally try to go easy on the way to work in the morning, primarily to avoid sweating too much. (7.5 miles in 40 minutes = avg 11 mph)

On the way home, I can push it more, since I know I'll just shower when i get home. (7.5 miles in 30 minutes = avg 14 mph)

The route is about the same eleveation both ways, with lots of small ups and downs, and one larger (1mile) hill up and down.

So still, I'm not going supper fast, though I probably get up to 20 or above on some flat parts...and about a mile of the trip is on a "chip and seal road", which really slows me down.