According to their statistics being hit by trucks and cars was not even in the top 7 death causes for 2010. The 7th place (influenza and pneumonia) killed 5 children. This means that getting hit by cars will save (at most) 4 children a year, of those 4, you would only save the ones who were crossing the street right as a driver was making a left turn because Google Maps told them (as opposed to say, someone who was drunk driving).
Of course, all lives are precious and won't somebody, please, think of the children so at this point the question becomes one of assignment of resources. You could assign resources to cure malignant neoplasm (killed 48 children), or to improve safety and reduce assaults (killed 18 children) or you could write a letter to Google to ask them to reduce left turns. I will let you decide what would be more effective.