I’ve always heard if one’s car breaks down on the side of road, said person is supossed to walk with traffic and not against it and this is safer for some reason. Likewise, for someone riding a bike. Why? If a car veers off the road towards the person and the walker/rider is moving with traffic, he or she won’t see the car; however, if the person is moving against traffic, he or she has a chance of doging or moving out of the way. Does this make any sense?
You should always walk against traffic, so that you can see the cars. You should ride with traffic, because on a bike (in the USA) you are generally required to follow traffic laws (vs pedestrian rules).
Chief Crunch, thank you. You rule. I have always thought that. Laws-smaws. I feel much safer going against traffic.
That includes while driving my car. 
Under the eyes of the law, bikes are the same as cars. I know this because my roommate my second year of college almost had his license suspended on account of a bike accident. So you are obligated to ride with traffic. However, it’s definitely safer to walk against traffic, so that you see oncoming cars.