I failed to protect the puppies?

a few days ago i posted about how i feed the dogs in my colonies and how there are 3 little newborns of whose survival was of utmost importance to me.............yesterday one of the little guys whom i had named Skids died when he came under a car.............i thought i could've ensured their safety but i did not do certain things that i should have...........i feel responsible for the pup's death and i think i' am gonna inform the animal authorities about this...........feel free to give any tips on how i can help the other 2 pups survive.......i don't have a backyard and hence building a kennel is out of the question.......