Who Is Responsible for Traffic Control on an Alberta Job Site?
TrafficIQ · · 6 min read
When a vehicle hits a sign, a worker is hurt, or an inspector stops work on a site, the first question is who was responsible for the traffic control. Many contractors assume the answer is the traffic control company. In Alberta, responsibility is shared, and each party's share comes from the Occupational Health and Safety Act, the permit, and the contracts on the job. This guide explains how those duties usually divide.
It is general information, not legal advice. Who is liable after an incident depends on your contracts, your insurance and what happened, so check those with your own advisors.
Every party on the site has a duty
Alberta's OHS Act rests on what the province calls the internal responsibility system: every party on a work site is accountable for health and safety. One company can also hold several roles at once. A general contractor might be an employer, a contracting employer and the prime contractor on the same job, and it has to meet the obligations of every role it holds.
How the duties divide
Part 1 of the OHS Act sets out obligations for each work site party. Here is how they apply on a job with traffic control:
| Party | What the OHS Act expects | On a traffic control job |
|---|---|---|
| Prime contractor | Coordinates health and safety across all employers on the site, and makes sure the owner, employers, suppliers and service providers know about existing and potential hazards | Required on a construction work site with two or more employers, so it applies as soon as a traffic control company works alongside the contractor |
| Employers | Protect their own workers and the public at or near the site, provide training and competent supervision, and share hazard information with the prime contractor | Each contractor is responsible for how its own crew works in and around traffic |
| Contracting employer | Makes sure the employers it directs comply with the OHS legislation, and passes on hazard information | A general contractor directing subcontractors, including the traffic control company |
| Service provider | Provides services that let the client comply, uses competent workers, and endangers no one through its own activities | The traffic control company preparing a plan or staffing a site |
| Supplier | Supplies equipment that is safe to use and complies with the legislation, and maintains it where there is a maintenance agreement | Whoever rents out the signs, cones and barricades |
| Owner | Keeps land and infrastructure under its control from endangering people, and tells all parties about hazards it has identified | The registered owner of the land where the work happens |
| Workers | Follow safety rules, use the controls and protective equipment provided, and report concerns | Everyone on site, including traffic control persons |
The prime contractor is the coordinator
The person in control of the site must designate the prime contractor in writing and post its name where people can see it. If nobody is designated, the person in control of the site is treated as the prime contractor and can be held accountable for failing to designate one. On a multi-employer site, settle this before the first shift.
What the traffic control company is responsible for
The contract sets the traffic control company's scope. Within that scope, it is usually responsible for:
- Preparing a traffic plan to the manual that applies to the road, if plan preparation is part of the job.
- Setting up signs and devices as the approved plan shows.
- Supplying trained traffic control persons with the apparel and equipment the job requires.
- Supplying equipment that is safe to use and complies with the legislation.
It is generally not responsible for decisions outside that scope, such as the layout of the work area, work that moves outside the plan without notice, or hazards that have nothing to do with traffic.
What stays with the contractor running the job
The contractor running the work keeps responsibility for the work itself and the hazards it creates. It also has to tell the traffic control crew when conditions change. If a new excavation opens or a material laydown area moves and nobody tells the crew, the gap is not automatically the traffic control company's.
Permits and contracts often make this explicit:
- Edmonton roads. Once an OSCAM permit is issued, the permit holder is responsible for installing and maintaining the traffic control as approved for the full duration of the work. See How to Get an OSCAM Permit in Edmonton.
- Provincial highways. Alberta's standard highway contract specification makes the contractor responsible for safely accommodating traffic over the whole site, even when it coordinates with other crews working nearby. The department can suspend work if the contractor fails to provide for public safety.
Where it gets complicated: sites with several employers
Responsibility is hardest to sort out on sites with several employers. Say a traffic control company is hired by a subcontractor, and another trade's equipment moves into the closure. The prime contractor coordinates the site, each employer answers for its own workers and activities, and the contracts and insurance policies decide who pays.
The OHS Act allows for some overlap. When two parties hold the same obligation, one can meet it for both, as long as doing it twice would only duplicate effort and having one party do it puts no one at risk. That only works if the parties agree in advance who is doing what.
Why the plan and the records matter
An approved traffic plan is the shared record of what was supposed to happen, agreed before the work started. When something goes wrong, it is what every party points back to.
Two other records help just as much:
- Hazard assessments. The OHS Code requires employers to assess a work site and identify existing and potential hazards before work begins, in writing, and to revisit the assessment when work processes or site conditions change.
- Inspection and sign records. Alberta's highway contract specification requires the contractor to name who monitors the traffic control, document site inspections, and record the location of every temporary sign daily. Even where a permit doesn't require it, the same habit gives you evidence of what was on site and when.
Before work starts: a quick checklist
- Confirm in writing who the prime contractor is, and post the name on site.
- Get the approved traffic plan and any permit conditions to every party.
- Agree on the traffic control company's scope, in writing.
- Name who inspects and maintains the signs and devices, and how often.
- Decide how changes to the work reach the traffic control crew, and who calls whom.
- Keep hazard assessments, inspection notes and sign records for the life of the job.
- Review your contract and insurance with your own advisors.
How TrafficIQ can help
TrafficIQ prepares traffic accommodation plans and strategies, supplies certified traffic control persons and equipment, and scopes each job with the contractor before work starts, so everyone knows who is responsible for what. See Traffic Management and Flagging & Site Services, or request a quote with your project details.
Last reviewed October 2026. This article is general information, not legal advice.
Sources: Government of Alberta, Obligations of work site parties; Occupational Health and Safety Act; OHS Code Explanation Guide, Part 2; Alberta Transportation, Specification Section 01552; City of Edmonton, OSCAM Permit.