I agree it's a typo, BUT doesn't hwy 11 run N/S and not E/W? I agree with the rest of your assessment, and I know this is a small detail, but he would not have been seen driving West on Hwy 11. It has to be Hwy 312 if he was driving West. MOO (if it was a major road). The subsequent statement is that he was seen travelling south on Hwy 11.
"The white Chevy truck was seen by a Rosthern RCMP officer driving in an unmarked vehicle, traveling west along highway 1 toward Rosthern at a speed recorded at 150 km/h. Police confirmed the license plate matched the initial report.
At approximately 3:30 p.m., the suspect vehicle was seen travelling south on Highway 11, south of Rosthern. To ensure the safety of drivers on the highway, the vehicle was directed off the road into a nearby ditch. "