I have an eight-mile commute in Atlanta. I make it on a twenty-year-old Trek road bike. I went to a compact double to give my old legs a break on the hills. I only have one section of about a mile that I really despise - three lanes uphill - everybody doing 60 in a 45 zone. I could extend my commute to about 9.5 by adding 1.5 on a bike path and rough trail and miss all that traffic. The question is should I buy an old mountain bike, add the rack and panniers and change my commute or just stick it out with the speed demons?