Hydraulic horns

A few days ago I had to go to Chittagong from Dhaka by an AC bus. The journey was comfortable. But I was surprised to see that almost all the buses and trucks on the trunk road were using "hydraulic horns" causing loud noise. This is causing much discomfort to the passengers as well as the people residing on both sides of the National Highway.
I recollect some years ago the govt banned the use of "hydraulic horns" by trucks and buses. Some "check-posts" were set up at the main entry points of Dhaka City where the police and Rab checked the trucks and buses entering the city. This proved to be very effective and use of these loud horns almost stopped. However, this menace has reappeared.
I would therefore request the law enforcing agencies to look into this matter and take corrective measures to save the pubic from "sound pollution."