Office of Operations
21st Century Operations Using 21st Century Technologies

Field Operations Guide for Safety/Service Patrols

Emergency Temporary Traffic Control

Temporary Traffic Control at a Traffic Incident Management Area

Utilizing Temporary Traffic Controls (TTC) at a Traffic Incident Management Area (TIMA) helps move road users safely and expeditiously past or around an incident, reduces the likelihood of secondary traffic crashes, and keeps motorists off the surrounding road system.

TTCs include devices such as traffic cones, arrow panels, and warning signs as well as the use of manual traffic control (flagging).

You should always:

  • Use safe practices for accomplishing your tasks in and near traffic.
  • Be aware of your visibility to oncoming traffic.
  • Take measures either to move the traffic incident as far off the traveled roadway as possible or to provide appropriate warning of blocked lanes.
  • Set up appropriate temporary traffic controls. Request additional traffic controls if the incident will not be cleared rapidly.
  • Update dispatch within 15 minutes of arrival at an incident, of:
    • Your upgraded assessment of the magnitude of the traffic incident, including the number and types of vehicles, injuries, and lane closures.
    • The expected duration of the traffic incident.
    • The expected vehicle queue length.
  • Reassess TTC devices regularly—every 15 minutes is recommended. Take some step, however small, to improve traffic at the incident scene, such as straightening or extending cone lines, relocating a responder vehicle, or reducing emergency lighting.

Photo of a Maryland State Highway Administration CHART emergency response unit.
Figure 7. Maryland State Highway Administration Coordinated Highways Action Response Team (CHART) Emergency Response Unit.

Safe Vehicle Placement

Vehicle placement at the time of initial response is important to establish safe and effective traffic control.

At a lane-blocking incident:

  • Place your vehicle in a visible location between the incident and approaching traffic. Activate your arrow panel to warn motorists and direct traffic around the scene as you set up your lane closure taper with traffic cones.
  • Relocate your vehicle as needed to best utilize the arrow panel once the traffic cones are in place.
  • Consider repositioning your vehicle to allow more room for emergency vehicles as additional resources arrive.
  • Confer with other on-scene agencies, when appropriate, through the incident command structure to ensure that emergency vehicle placement is optimized for scene safety, on-scene operations, and traffic flow past the scene. Consider staging additional response vehicles off-site until needed.
  • Continue to look for opportunities to improve traffic flow and scene safety.

Emergency Light Use

The appropriate use of emergency lights-high-intensity rotating, flashing, or strobe lights-is essential.

Emergency lighting is most effective when a traffic incident blocks travel lanes and traffic control devices are not yet deployed. Once responders deploy emergency temporary traffic control, the emergency lighting should be reduced. Emergency lighting does not provide traffic control and is not considered a traffic control device.

Excessive or misdirected lighting can create confusion for approaching road users and increase the chances for secondary crashes. Motorists approaching a traffic incident from the opposite direction on a divided facility are often distracted by emergency vehicle lighting and slow down, sometimes abruptly, to look at the traffic incident as they pass, posing a hazard to themselves and other travelers. The lingering effect of this distraction contributes to increased congestion and resulting delay.

  • Minimize the use of emergency lights by multiple response vehicles as channelization and advance warning are established.
  • Monitor and adjust emergency lighting during the incident to improve the visibility of traffic control devices and reduce onlooker delay.
  • Use arrow panels instead of flashing lights to provide traffic control.
  • Use emergency lights-in accordance with applicable laws and operating procedures-when:
    • En route to a confirmed incident with injuries or blocking a travel lane.
    • Using facilities, such as emergency crossovers or the shoulder-if authorized to do so-on which the general public is not authorized to drive.
    • Assisting stranded motorists, law enforcement, or other responders in a hazardous location.
    • Occupying a travel lane or any portion of a lane for an incident when the arrow panel is not effective.
    • Reentering the travel lanes from a parked position on the shoulder. Use rear-facing emergency lights until you reach travel speed.
  • Do NOT use emergency lights when:
    • En route to a non-emergency incident, such as a stalled vehicle on the shoulder.
    • En route to an unconfirmed incident.

Arrow Panel Use

An S/SP vehicle with an arrow panel is probably the most effective temporary traffic control device available. Proper use of the vehicle-mounted arrow panel or dynamic message sign (DMS), if so equipped, is essential for emergency temporary traffic control at an incident scene.

The arrow panel, used in conjunction with traffic cones and other traffic control devices, provides positive guidance to direct approaching traffic away from a blocked travel lane at an incident scene.

  • Use the arrow panel in Arrow mode only to indicate a blocked travel lane.

Image of a left pointing arrow.
Figure 8. Arrow Panel Indicating a Blocked Lane.

  • Use the arrow panel in Caution mode when on or near the shoulder of the roadway.

Images of two arrow panels in caution mode; one consists of four yellow lights, one in each corner of the panel, and the other consists of four yellow lights in a straight horizontal line running through the middle of the panel.
Figure 9. Arrow Panel Indicating Caution.

  • Do not exceed the manufacturer's suggested speed, which is typically 40 mi/h, with the arrow panel in the upright position. Wind damage to the panel, mounts and/or vehicle may result.
  • Be aware of your vehicle's overall height with the arrow panel in both the lowered and upright position.

Traffic Cone Placement

S/SP operators must be experts in setting up short-term traffic control to make incident scenes safer. Traffic cones serve as safety devices as well as effective traffic control devices.

Traffic Cone Placement for Lane-Blocking Incidents

  • Carry at least 16 cones on your vehicle.
  • Set out traffic cones in a taper to guide approaching traffic into available lanes to safely pass the incident.
  • Start deploying cones at the rear of your vehicle and work your way upstream.
  • Reinforce and straighten traffic cone lines and tapers after their initial placement to increase effectiveness and maximize visibility of the cones.
  • Remember to always face traffic while placing or removing cones.
  • Space cones equally at least 20 feet apart.
  • Use 12 cones for the lane closure taper, which should be approximately 250 feet, and four cones along the activity area to quickly make the scene safer.
  • Place cones around response vehicles and place at least one cone downstream past the incident to allow a parking spot for the ambulance or EMS vehicle.
  • Use striping marks as a distance reference to help with cone placement. Roadway striping on freeways typically has a 10 foot painted stripe and a 30 foot gap.
  • Increase the number of cones and the distance between cones as the speed of approaching traffic increases. This gives motorists more time to react, slow down, and merge.
  • Delineate traffic tapers with clean, reflectorized cones.
  • Use only reflectorized cones when working at night.
  • Borrow additional cones from other responding units or request some from another S/SP unit through dispatch if needed.
  • Improve traffic flow by moving the transition taper further upstream from the activity area as additional traffic controls are put in place.

Diagram showing the appropriate placement of vehicles and equipment at the site of an incident.
Figure 10. Emergency Temporary Traffic Control Example.

Positive Traffic Control

Providing manual positive traffic control, also called flagging, at an incident scene reduces rubbernecking and helps keep traffic moving smoothly past the scene.

  • Have qualified flaggers provide manual traffic control if possible, but any response personnel can provide it if necessary.
  • Do not use bystanders, good Samaritans or other untrained personnel for traffic control duties.
  • Give commands or directions to traffic in a clear, courteous but firm tone.
  • Accompany verbal commands to "stop," "slow down," and "proceed" with appropriate hand movements or the use of a "Stop/Slow" paddle or flag.
  • Note that whistles can also be an effective tool.
  • Position yourself at a safe location adjacent to the wrecked vehicles when providing positive traffic control in the activity area.
  • Position yourself at a safe location near the beginning of the taper when providing positive traffic control in the transition taper area.
  • Make eye contact with the drivers of approaching vehicles to encourage them to pay attention to their driving and not the incident. This will increase the flow of traffic past the incident scene, reducing delay.
  • Avoid providing individualized directions to motorists as this can create more congestion by slowing traffic. Remember, your job is to keep traffic moving.

Diagram shows three commands for controlling traffic with hand held paddles that read STOP or SLOW, and three commands for controlling traffic using a red flag. Commands include proper body positioning and paddle or flag use to stop traffic, to let traffic proceed, and to alert and slow traffic.
Figure 11. Flagger Commands for Emergency Positive Traffic Control.

Advance Warning and Queue Protection

When an incident occurs, there is a significant probability of a secondary incident, which is often more serious than the initial event. S/SP operators play an important role in reducing these secondary incidents.

Vehicles approaching at high speeds will often encounter the stopped queue of traffic long before the arrow panels and scene emergency lighting are visible. This high-speed traffic does not expect stopped traffic and needs appropriate warning.

Special incident management advance warning signs placed by you or other responders provide the warning to approaching motorists. These signs may be a special fluorescent pink color with legends such as "INCIDENT AHEAD" and "BE PREPARED TO STOP."

Coordinate with responding units who are either already on the scene or are arriving on the scene to place the advance warning signs.

  • Double back and place the advance warning signs once the immediate scene is secure if you are the initial responding unit and additional units are not available to assist.
  • Place the signs well in advance of the queue. Relocate them if needed.
  • Act as the "eyes and the ears" of the TMC if one is operating in the area. Maintain continual communication with the TMC while on an incident scene so that traffic warning devices such as DMS can be updated with accurate information for approaching motorists.
  • Obtain additional signs, if needed, from other response units and place them on both sides of the roadway well in advance of the scene.

Examples of three incident warning signs, one that reads 'Emergency Scene Ahead,' on that shows a lane narrowing/closing ahead icon, and one that reads 'Be Prepared to Stop.' All three signs are pink.
Figure 12. Incident Advance Warning Signs.

Dismantling the Incident Scene

At the conclusion of an incident, help facilitate the safe removal of all components of the incident scene. Work with other responders to develop a plan for breaking down the scene to safely remove all remaining responders, responder vehicles, and TTC devices.

  • Remove all debris from the travel lanes and shoulder.
  • Remove traffic control devices in the upstream direction. Start at the termination area and work your way up to the advance warning area.
  • Make notification to dispatch when the lanes are reopened.
  • Be alert for impatient motorists. With the incident victims and vehicles removed, delayed drivers will not be as cautious and may not see you.