Final answer:
When a traffic signal changes and a pedestrian is in the crosswalk, the pedestrian retains the right of way, and vehicles must yield until the pedestrian has safely finished crossing.
Step-by-step explanation:
If a traffic signal changes while a pedestrian is still in the crosswalk, the pedestrian has the right of way. The safety of pedestrians is paramount, and they are given priority when signals change to ensure they can finish crossing the street safely. Vehicles, whether turning left or right, must wait for pedestrians to clear the crosswalk before proceeding.