Bike safety includes a few key components: a good helmet, reflective gear and bike reflectors to make you visible, and knowing how to ride on trails and on the road with others.
The League of American Cyclists offers a good description of the right gear to stay safe and comfortable when you ride, as well as riding tips on its smart cycling tips page.
When it comes to kids and bike safety, Safe Kids Worldwide offers a video tutorial on finding the right bike helmet fit for a child.