When should a vehicle using its horn signal be used on the road?
Mr. Nguyen Van Thanh, residing in Dien Chau district, asked: In what cases is it allowed to use the horn signal of a vehicle participating in road traffic?
Reply:
Article 21The Law on Road Traffic Order and Safety 2024 stipulates theuse whistle signalas follows:
1. The horn signal of a vehicle participating in road traffic may only be used in the following cases:
a) Signal to road users when a situation that may endanger traffic safety occurs;
b) Signal to prepare to overtake.

2. Do not use the horn continuously; do not use the horn with an incorrect volume; do not use the horn from 10:00 p.m. the previous day to 5:00 a.m. the following day in densely populated areas, medical examination and treatment facilities, except for priority vehicles.