What is considered the least desirable method used to control traffic?

The baton system is considered the least desirable method for controlling traffic primarily due to its reliance on personnel to manage traffic flow effectively. This manual method can often be less efficient and more prone to errors when compared to other options. While a baton can be effective in certain situations, it requires constant attention from the flagger and does not provide clear, automated communication to drivers.

In contrast, light signals and barriers provide more organized and consistent traffic guidance. Light signals can manage traffic flow with minimal delay and communicate instructions to drivers clearly, while barriers physically restrict movement and create safe zones for construction or maintenance work. Manual signaling, although dependent on flaggers, often has protocols that can help mitigate ambiguity compared to a straightforward baton system. Therefore, the baton system's limitations in managing traffic safely and effectively make it the least desirable option among traffic control methods.