New York State Local Technical Assistance Program

When can a single flagger be used?

The use of a single flagger is should only be considered on a straight, low volume road. When used, a single flagger should stand on the shoulder on the opposite side of the road from the work area and should be clearly visible to all approaching vehicles. Using a STOP/SLOW paddle the flagger should completely stop traffic in one direction prior to allowing the other direction to proceed through the work zone.

Here’s a check list to check to see if a Single Flagger is feasible:

Is traffic less than 400 vehicles? (How to estimate traffic)

Is there adequate sight distance in both directions? (distance to last warning sign before the work zone)

Guidelines for buffer lengths
speed (mph) length (ft)


25 115


35 250
40 305
45 360
50 425
55 495
60 570
65 645


Is the flagger able to stand safely on the opposite side of the highway from the work? (Adequate shoulder and escape route)

If you answer no or cannot answer the question definitively, you should use a two-man flagging set up.

In most situations, a minimum of two flaggers should be used. Placing a flagger at each end of the work zone allows full control of approaching traffic. For success of the work zone the two flaggers must maintain communication at all times. Communication can be visual, through two-way radios, or by having the driver of the last vehicle carry a flag or token to the other end of the work zone, this serves as an indicator of the last vehicle in the queue. Communication allows for the safe passage of vehicles through the work zone.

Cover of the CLRP workzone safety pocket guide
Work Zone Safety
Pocket Guide

Remember, “Your safety, the safety of your crew, and the safety of the monitoring public are more important than any construction, maintenance, or utility operation being performed.”

Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License icon

This work by the Cornell Local Roads Program (CLRP) is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.