I used to commute 7 miles too. Mine was all on road, in city traffic. For me, while it was fun bike commuting to work, it just didn't work. I'm in public service, so I'd have to leave my heavy gear at work, and haul a backpack with my uniform and some light gear. I'd arrive to work sweaty, and have to change into uniform and gear. I already work over 12 hrs a day, so the commute was in the dark half the time. It was a nice experiment, but in the end, it was too much to juggle for me personally.