Absolutely. My two commuters are old hard tails with the fork replaced with rigid. You can run any size tires (I go from Nokian studs in the winter to 1.5's the rest of the year on one of the bikes), add fenders or racks if you want, and you got plenty of bail out gears if you need em. Plus you don't worry about em getting to dirty.

As for my advice, make yourself visible. I can't believe how many cyclists I see out there playing in traffic that aren't visible. I don't care if you have a shoulder or not, get visible. My feeling is that if you are in any significant, fast traffic, the only option is hi-vis neon green jersey with some daytime visible tail lights if you can afford it.