How many times should the high and low beams be alternated in Subject 3?

[MacAlan]

In Subject 3, the high and low beams should be alternated at least twice. Here is some relevant information: Low beam: The illumination distance of the low beam is approximately 30,000-40,000 mm. Experiments have shown that when driving at 55 km/h at night, if you immediately apply the brakes upon spotting an obstacle, the stopping distance is exactly 30,000 mm. This means that if you stop immediately upon spotting something within the low beam's range, there will be no gap between the car and the object. High beam: High beams should only be used when there are no other lighting facilities on the road and no oncoming vehicles. Otherwise, they can severely interfere with the vision of other drivers and even cause traffic accidents. Be careful not to mistakenly use high beams instead of low beams.