Key Terms

Activity area - The section of a roadway in which work takes place. This area includes the work space, traffic space, and buffer space, and is a component of the roadway work zone.

Buffer space - In a roadway work zone, the area between the moving roadway traffic and the activity area (or "work space") of the roadway construction project. The buffer space is present to protect workers from moving traffic and to provide a safeguard should a vehicle leave the roadway.

Channelizing device - Roadway warning devices such as retroreflective barrels, traffic cones, tubular markers, and other devices that serve to move roadway traffic away from the activity area of a roadway work zone.

Flagger - A person who controls the flow of traffic through a roadway work zone by using hand-signaling, most often by using a STOP-SLOW sign.

Retroreflective - The property of an engineered surface that causes any light that hits it to reflect directly back to the source. Retroreflective apparel and traffic control devices are a requirement of nighttime roadway work.

Roadway work zone - Any area of a public roadway in which road conditions have changed due to the presence of work activity on the roadway.

Temporary traffic control (TTC) - A system of devices, communication, and other warnings designed to alert roadway users to roadway conditions that have changed due to work activity.

Work space - The section within a roadway work zone where the roadway work is performed.

To learn more about Roadway Work Zones visit our Worker Safety in Roadway Work Zones Online Training web page.