One of the best ways to avoid injury while biking is to

Avoid riding on roadways. If there is a sidewalk you could ride on nearby, use it. Drivers get a little nervous if they're sharing the roadway with a bicycle. Avoid riding too long without breaks, you can get tired out and unintentionally harm yourself or others. Drink lots of water on the way, and wear helmets at all times, no matter how stupid you think they make you look. :)

Primary effectit is the most accurate.