I have a single speed bike and find it hard to ride on the road when i'm tired.?

A single speed jump bike has to be just about the worst choice for commuting. A good multi speed road bike would be far better. It would be faster on the flat sections and the gears would allow you to ride uphill with ease. Moving faster on the road make cars much less frightening, they aren't going all that much faster than you are. Faster speed also would make it much more dangerous riding on a sidewalk. You may have lights on your bike to advise pedestrians, but really it is up to you to avoid them, they do not have to yield to you since you have no business being where you are, single speed or not. My personal favourite commuting bike would be a good touring bike, steady and stable with mounting points for mudguards and a rack to carry your gear.