What must you remember in the case of bus doors?

Your answer correctly includes the essential regulations regarding bus doors.

1. The rule about keeping the door areas free while driving is critical for safety. This ensures that passengers can board and alight safely and reduces the risk of accidents caused by obstructions.

2. The requirement to only set off when all doors are completely closed is crucial for preventing injuries. A bus that starts moving with open doors poses a significant risk to passengers.

Together, these rules emphasize the importance of safety in public transportation. The incorrect option regarding opening doors during summer is not allowed while driving, as it could compromise passenger safety. Therefore, the combination of your selected options is entirely correct and reflects the importance of these traffic regulations.