Children often have trouble telling where a sound is coming from. They may hear a vehicle coming but may look the wrong way. Until about age 8, children typically lack a sense of danger. They really don't understand how vulnerable they are. For them, a traffic signal may seem to take forever to change.
Children have trouble judging complex chains of events.
For example, it's hard for them to see an accident situation developing. They may focus only on things that interest them the most. For example, an ice cream truck across the street may be much more interesting than the dull brown car coming down the street. They often believe that grown-ups will look out for them. They may think that because they can see the car coming, the driver can see them, too, and will know they are about to cross the street from between two parked cars.