Traffic Control Guideline #3

Regardless of the complexity of the temporary traffic control, planning is essential to ensure the safety of workers, motorists and pedestrians. Traffic control plans may range in complexity from a few notes on a tool box talk form to a comprehensive "engineered" plan. However, the fundamental principles of traffic planning are consistent for all levels of traffic control planning.

What is a Traffic Control Plan?

It is a site-specific or activity-specific written plan to temporarily divert traffic in a "controlled" manner. The intent of a temporary traffic control plan is to clearly guide traffic from its normal course while creating a safe workzone. The most effective way to achieve this is to direct traffic with as little interference in the normal traffic flow as possible. This is essential since studies have shown that the more drastic the change from the normal driving pattern, the greater chance there is of a crash occurring.

Traffic control plans may reference a figure(s) from the Traffic Control Manual for Work on Roadways but must also relate the figure(s) to the specific characteristics of the site (examples are posted speed, roadway geometry or type of vehicle users).

Traffic control plans may range from a few references on the toolbox form to an engineer-designed plan, depending on the complexity of the situation. There is no "one" plan. The Traffic Control Plan Template (32KB PDF) may assist you in developing your traffic control plans.

Benefits of Traffic Control Planning

Taking the time to assess traffic control needs and develop appropriate traffic control plans is beneficial in many ways. It increases productivity, decreases downtime, improves organization, ensures overall safety, increases public awareness, reduces liability, and enables authorities to better enforce traffic laws.

What to Consider in Your Traffic Control Plan

Always consider temporary traffic control from both the workers’ and motorists’ perspectives. Workers want traffic control that allows them easy access to the site while providing protection, and is easy to erect, maintain and dismantle. Motorists want traffic control that has little interference with their normal driving pattern and is clear and justified.

When determining what will influence the way motorists should be directed and how they will react, consider both the site factors and procedural factors affecting traffic.

Site factors are characteristics of the work location (e.g. hills, curves, passing lanes, surrounding businesses / accesses, speed zones, intersections, types of vehicles, volume of vehicles, competing advertising signs, etc.).

Procedural factors are characteristics of the work process (e.g. "eye-catching" activities, such as rock scaling, heavy equipment, lay-up areas, congestion, lane width requirements, equipment travel through the site, etc.).

Using the Traffic Control Manual for Work on Roadways

Once you have assessed your site and determined all the factors that may affect traffic flow, use a site diagram to develop a "plan view" of the site. Identify the significant site and procedural factors on the diagram. Then use the Traffic Control Manual for Work on Roadways to determine the best approach. This manual describes the "fundamental principles" of temporary traffic control and depicts numerous, commonly encountered temporary traffic control combinations for various types of roadways.

It is important to realize that the temporary traffic control examples contained in the manual may not address every situation. These examples are considered "minimums" and may need to be modified or expanded to fit the specifics of the situation. However, any modifications must be made according to the "fundamental principles" of traffic control.

If Your Temporary Traffic Control is Ineffective

If the majority of motorists are disregarding your temporary traffic control, it is an indication that the plan is not working. If a motorist is confused, they will do one of three things: stop, make the wrong choice, or make the right choice. If the traffic control is ineffective, you should reassess the traffic control plan to determine the cause. Look for the following:

Conflicting Messages – Trying to direct motorists to do something that seems contrary to the situation or surroundings (e.g. installing a speed reduction at the beginning of a passing opportunity so that motorists are torn between obeying the traffic signs and taking advantage of the brief passing opportunity).

Inappropriate Messages – Using the wrong device to direct traffic. This usually occurs when an attempt is made to make use of the signs / devices available that may not accurately reflect the work or the intended direction (e.g. using a right lane drop when a left one is needed).

Site Layout – Motorists’ response to traffic control may be affected by site factors such as curves or hills where motorists need additional warning in order to react or where commercial vehicles need a run to climb a hill.

Information Overload – Motorists are receiving too much information in too short a time period, therefore, they are unable to respond appropriately. This may occur when motorists are directed to perform two things at once (e.g. merge and reduce speed) or when there are too many signs or too much activity competing for their attention (e.g. lots of big billboards beside the traffic control signs, or heavy equipment congestion close to the traveled portion of roadway). Try to keep the traffic control simple, positive and directive with little need for motorists to make a "choice".

Length of Speed Zone – Motorists will reduce their speed for approximately 12 to15 seconds. If they do not encounter the active work area, a traffic queue or other justification for the reduced speed within this time, they will resume their original driving behaviour.

Unnecessary Devices or Drastic Changes – Traffic control devices must be supported by the activity the motorists see. Motorists will eventually disregard devices they do not feel are warranted (e.g. a temporary speed zone left up during the evenings and weekends but all activities and equipment are cleared off the road at the end of each shift). Drastic changes in the normal driving pattern will also cause problems for motorists (e.g. a 90-degree detour or speed reduction of greater than 30km/h).

For more complete information on traffic control planning, refer to the "Fundamental Principles" section of the Traffic Control Manual for Work on Roadways.

Prior to Performing work on roadways, contact the Ministry of Transportation District Office for local policies and traffic information.

Ministry of Transportation
Human Resources Branch
Health and Safety Section