Near roadways across BC and Alberta, in particular along the Yellowhead and Coquihalla Highways, you may have noticed our crews busy at work on the Trans Mountain Expansion Project. Along with the large pieces of equipment like excavators and side booms, you’ll also see electrical warning lines, lane closures and variable speed corridors; all to ensure the safety and security of the public, the environment and our workforce while minimizing disruptions to those travelling in the vicinity of our pipeline route.

Some of the things you might see between Yellowhead and the Coquihalla Summit this summer:

Variable Speed Corridors

Between Yellowhead Highway and Hope you may encounter a few variable speed corridors during your road trip. There are three, 20-minute intervals totaling a possible 60 minutes of delays on your trip, for the entire length of the highway corridor. This is monitored through our extensive traffic management program.

For updates on the latest road conditions, please visit

Traffic Flaggers

Often, large pieces of equipment like excavators are moved from worksite to worksite and due to their large size, they sometimes require traffic flaggers to help safely navigate them as well as traffic through active construction sites. When you see a flagger or any roadside worker, ensure you slow down and drive with extreme caution, stay alert and minimize any distractions.


The electrical warning flags monitor the height of electrical lines at all worksite access points so those driving through with large pieces of equipment can see how close they are and safely navigate around the live wires. In the industry, we call these goal posts. The flags also give information to crews if the electrical line is getting too hot as the flags will begin to sag.


If you are travelling in the evening, you may encounter signs that we are doing rock blasting activities at night in Hope, but we anticipate this will not require any lane closures.

Wildfire Activity

Trans Mountain is also working closely with the Ministry of Transportation and Infrastructure (MOTI) and the BC Wildfire Service to keep the highways clear for forest fire emergency activities. In those cases, we remove everything from the highway and shut down our activities.

In some cases, our crews have been in the right place at the right time. On numerous occasions this summer, our quick-thinking crew members jumped into action after vehicles caught fire near the ditch and our water truck drivers managed to be on scene before the fire spread and put it out before the emergency fire crews arrived.

If you are driving in the Lower Mainland:

Particularly along United Boulevard, you may also face delays, lane closures or disruptions, but this is all done in the name of safety for everyone working on the Project and travelling in the areas where we are working.

For more information about construction or to sign up for our regional construction updates, please visit our interactive map.