Which of the following is NOT a type of traffic control device?

Speed bumps are primarily designed to slow down vehicle traffic on roads and are not classified as traditional traffic control devices like barricades, warning signs, or flashers. Traffic control devices are specifically meant to regulate, warn, or guide traffic in a consistent manner, while speed bumps serve a different purpose related to traffic calming. Barricades are used to direct or restrict traffic flow; warning signs alert drivers to specific conditions or hazards; and flashers provide visual signals to draw attention to certain road situations. Understanding the definitions and roles of these different devices helps clarify the distinction and supports proper traffic management practices in work zones.