For example, hitting an elderly person in order to avoid hitting a small child.
A not even that much intelligent car would have notice a long time ago that there two object on the street (no need to identify them. There are just 2 big masses on the road), and the if car is kept on the same trajectory it is set for a collision course.
the would already have started pre-braking, sounding some imminent collision alarm, blinking lights on the dashboard
By the time you reach the situation where a human would need to steer some way or another, a car with anti-collision system would have slowed down and stop at rest (unless the driver has overridden the system by voluntarily smashing down the accelerator against all car's alarms).
No need for complex recognition and identification of pedestrian. Just plain simple recognition that there are 2 masses of significat size.
No need for complex ethics engine evaluation, just being able to notice that said masses currently occupy a place that is intersected by the current trajectory of the car.
No need to aim for one while sparing the other, just slow down and brake well enough in advance (and cars electronics are much faster at noticing and reacting as human's slow reflexes and limited attention (or lack of) ).
I'm not speaking about some potential futuristic technology. I'm speaking about car that are street legal and currently circulating on a road near you. They're not even self driving, but they are already able to efficiently avoid collisions.
We haven't already started producing self-driving car beyond a few prototypes at google's lab, and we already have the necessary technology to avoid both deaths.
All these "ethics in robotic cars" are nice though experiments for a highschool's philosophy classes, but they are completely out of touch with technology. For any of these though experiment, the technology will reach a development level where casualities can be avoided a long time before a car's A.I begin to be able to have an ethics discussion with the philosophy teacher about the value of life.