From CHiPs Online:
As Ponch and Bobby pull Amy and the baby from the sinking car, Kathy and Grossie mysteriously appear to watch.
While Ponch and Bobby help get Amy and the baby out, the car hardly sinks. When everyone's safe and the weight inside the car is reduced, the car plunges down below the surface.
Kathy Linahan is a motor officer...but in one of the final scenes, she gives Amy a ride in a cruiser.