What is the whistle signal for "stop" in traffic direction?

The whistle signal for "stop" in traffic direction is indicated by one long blast. This signal is universally recognized among traffic control personnel, and its purpose is to quickly and clearly communicate to drivers that they must halt their vehicles.

A long blast is effective in catching attention and is distinct from other types of signals, which helps to ensure that it stands out amid the noise and activity typically present in traffic situations. This clarity is vital for maintaining safety on the road, as it reduces ambiguity and helps prevent potential accidents by providing a straightforward instruction to drivers.

In contrast, other signals such as two short blasts or several short blasts are often used for different purposes, such as indicating the need to slow down or prepare to stop rather than a direct command to stop immediately. A continuous tone might also convey a sense of urgency but is not specifically designated for signaling a stop, making one long blast the standard for stopping.