Now that I think about it, the last time I was there I don’t remember any oil tanker traffic, especially in Provo Canyon or from Heber up to 1-80.
No tankers in Provo canyon on Hwy 189. They roll on Hwy 40 from the oil fields east of Heber right through town carrying crude to SLC refineries. I estimate at least 1000/day counting both delivery and return trips.
A pipeline is proposed and IIRC in the works but we all know the issues a pipeline project entails.
I live north of there but often travel to Heber for business.