I believe autonomous vehicles are a huge overkill for what can easily be solved via decent public transportation. Public transportation via autonomous / centrally controlled vehicles would be way easier if the amount of private cars on the roads were reduced. And I'd guesstimate that a great majority of people using cars could easily switch to electric bicycles or mopeds. And that's a huge step forwards, as these vehicles are less likely to kill you if they hit you, and can steer away more easily. Add to that them being way more clean and fuel- and space-efficient in comparison to cars, leading to much more efficient use of both road- and parking-space, and of raw fuel. Also, this may be a local phæenomenon, but lots of large chain-stores offer delivery services, along with many small shops. In my quartier in the Northern European parts Istanbul, I can order from a bunch of chain stores, lots of restaurants (using yemeksepeti.com) and many tobacco shops.

So there's a chance that the cars sensors would spot him. Plus the sensors will be tied to the speed the car is doing so will always attentively watching in the range of where children can come from.

Further to this you can plug this kind of data into an autonomous vehicle and train it to avoid kids.

Humans will probably never have proper driving simulation testing like pilots do because it's too expensive.

So in these extreme events I'm confident that autonomous cars will be better prepared. Perhaps there will still be cases where the child still dies but it will be less.