First off I'd like to say I'm sorry about the dog. Unfortunately accidents do happen.
Their parents walk them several times a day and are ALWAYS on leashes...not this morning. No parents and no leash, but they were still walking on the side of the road.
Who's to say how they got loose. It wasn't like the OP always sees them running loose. Maybe someone working on the house let the dogs get out.
When I was a teen we took my grandmother's dog because she moved and couldn't take the dog with her. My dog had never gotten out before but one day the new dog found a way out and my dog followed. Unfortunately my dog was hit by a truck. The driver stopped but my dog ran off into the nearby field. The driver stopped by the house told us what happened. My Mom and I found my dog but it was too late. We found how the dogs got out and fixed the fence. But it was too late. Damage already done.
I also know someone who has a 5yr old GSD who just started escaping. Never got out before and just started. So they made repairs to the fence to keep the dog from digging under the fence.
I almost hit a neighbors' dog the other day. There was no traffic so I braked hard. Luckily I missed the dogs. It was not the first time I have seen the dog loose so the owners I feel are neglectful.
Another time when I was walking my dog I saw a dog loose. Since I didn't know the dog I turned around to walk a different way. I immediately heard tires screeching and saw the dogs running back in the direction it came from. Then it saw myself and my dog and followed us home. It even tried to follow me in the house. It showed no signs of aggression toward me or my dog. So I put my dog in the house and let the dog in the backyard. I caled the humane society but since it was Sun no one was there. So I called the sheriff's dept. Again since it was Sun no one would come. The only option I was given was to take the dog to the humane society myself. Since I didn't know the dog I wasn't about to put him in the car with me. Luckily when I went looking for the owner someone recognized the dog and we took him home. No one was home. A few weeks later I saw the owner walking the dog and stopped to talk to him. He said his wife let the dog out and the dog popped the latch. He said he talked to his wife about leaving the dog out.
Point is accidents happen. Who knows what all happened to lead to the dog getting hit. Some people are coming off like they are perfect. Nobody is! Period!