During your conversation with Jane, you mention that she could decrease her chance of injury in a car accident if...

During your conversation with Jane, you mention that she could decrease her chance of injury in a car accident if she secured her wallet in the glove box and placed her purse and other loose items (such as compact disk cases and books) in the trunk.  Why would this practice be safer?  Why is it important to secure both small and large items?  Explain your answer in terms of Newton's first and second laws of motion.