During what hours may a driver sound their horn in built-up areas for emergencies?

In built-up areas, it is important to minimize noise pollution during nighttime hours to ensure that residents are not disturbed. The legal restriction on sounding the horn is designed to balance the need for emergency communication with the need for peace and quiet during late hours.

The correct answer indicates that a driver is permitted to use their horn for emergencies specifically between 11:30 pm and 7:00 am. This restriction exists to reduce disturbances late at night and early in the morning when many people are likely to be sleeping.

During these hours, using the horn for emergencies is acceptable to alert others while still respecting the nighttime environment. This promotes safety while also considering the well-being of the community. The other timeframes mentioned in the options are either too broad or suggest inappropriate hours when unnecessary horn use might lead to disturbances, hence why they don't align with the established regulations.