If the whole pipeline is 36" except for a small part that is 30" doesn't that make the whole pipes throughput essentially 30"?

Came here to shout at the horror show being planned with this crude oil pipeline crossing the Cascade Mountains, a pristine area which is in the Ring of Fire.

Then I read the details and holy fuck what a boondoggle! IF this shit doesn’t destroy the environment, Canadian taxpayers will still be in the hole for tens of billions of dollars. This whole thing stinks of corruption. Someone is getting sweet kickbacks.