The one our laws set forth.
Frankly, it'd be foolish to design a vehicle to purposefully swerve out of control to avoid a person, even a child. You'd be putting everyone else around you at risk and still potentially failing at the original objective. OTOH, I can see future generations of this automation being capable of regaining control of the vehicle in situations that would have been impossible for humans to survive. But I digress....
You think it's wrong to have a cold, calculated, and socially agreed upon answer to no win scenarios, in exchange for saving 40,000 annually? Let's say you will not change the no win scenario, but you CAN save those 40,000 people.