I'd go with something like the Continental Terra Speed in 35mm. Aggressive looking knobbies but don't be fooled this will be a quick tire on pavement. I've ridden Continental's 2.2" knobbie tires with the protection layer and black chili compound on pavement - quick and long lasting.
Being even five minutes slower on your 30 mile route won't ruin your day. 5 seconds of sliding out on gravel will.
The most common way of crashing for me is always around a corner, half the time at low low speeds transitioning from pavement to gravel or arriving at a pit stop. I really like more aggressive side knobs just for this.