The four seconds is problematic for me for a number of reasons. In an urban environment you should be able to come to a stop in much less distance than your vehicle can cover in four seconds, in a modern car this should even be possible if one of the braking circuits has failed*. This is with a meatbag in control, the reaction time for an automomous car would be much quicker and sounding the horn to warn the pedestrians would be near instantaneous.
Even if we assume a trolley bus with a long stopping distance it is still absurd as an automated system would not need to rely on sensor fitted to the bus alone, it would use external sensors fitted along the route. If it cannot stop in the distance that can be seen to be clear then it is going too fast!
The scenario also fundamentally ignores that the pedestrians will also have four seconds or so to notice and react to the oncoming vehicle, particularly after it has sounded a warning, the chances of them standing still while the vehicle manoeuvers is very low. It is probably better to brake in a straight line, being predictable, and hope the pedestrian get out of the way.
* An EV could have a tertiary braking system in the form of regen or even emergency reverse drive of the motor.
The scenarios should be far more inventive, for example, if an autonomous vehicle detects a human controlled or apparently out of control vehicle about to hit pedestrians should it intervene by hitting that vehicle?